My father called me the other day and said he is ready to buy his first gas piston AR, he already has a LaRue OBR and a KAC so he is looking to try a piston gun. He is a stickler for fit and finish, so he wants something built like a tank and accurate. He is willing to spend in the $2500 range for the gun without optics so I tried putting a list together for him. Here is what I have come up with.
Barrett Rec7 Gen II
PWS MK116
H&K MR556
Sig 556
LWRC

Right now we both are leaning toward the Barrett Rec7 with the PWS mk116 is a close second in our minds. However what would be yalls choice and is there one you would absolutely stay away from and why?

First of all, you can not have a gas piston rifle square off with out the LMT

but for me...PWS MK116
I own a mk114 and love it, the lightest piston AR, runs great, and uses a long stroke piston system designed with the AK in mind. That doesnt mean it is an AK-AR, it is only similar based on the fact that it is long stroke instead of short stroke like the other AR piston system. The benefits are opinionated now, due to how far along most piston rifle manufacturers are with their designs.  

I also hear the Barret is "the most underrated" out of the piston ARs.

But you can get a PWS MK116 plus an aimpoint for the price of an LWRC. You could get an LWRC and PWS for the price of the HK.
Sigs are supposedly decent but I have no experience, just hear they are hit and miss

Just want to also mention, I would take the Scar 17 over all of the rifles you listed with the exception of maybe the Barret and PWS
My order would go
PWS ( because I love mine)
Barret ( because I want one bad)
Sig (dirt cheap for a piston rifle)
LWRC (cheaper than the HK, and probably the prettiest out of all)
HK(too expensive and not the same quality as the 416 according to some 556 owners on here)

Thank you for you're input, you have pretty much the same opinion as what I had. The reason we are leaning toward the Barret or the PWS is because we like the design of the gas systems on each. How is the build quality on the PWS? I have a Ruger that I bought dirt cheap that is a nice rifle, but I am not crazy about the short gas system although it has been flawless through the few thousand rounds I have put through it.

SCAR or a LWRC 6.8 that takes the 6.8 pmags.

He looked at the scar and liked it, but he is set on an AR. We would also like to keep it in the 5.56 family, much easier on me when reloading. I already do 9 different calibers.

I like my IC, ymmv.

Love my IC, the ambi lower is tits.

I'll pass on the 416, it's great but not for the price and features it's missing from all the other models.

The PWS!  I own several and love them!  The fit and finish is excellent and they are well built rifles.

from personal experience i own a Sig556 and a LWRC M6, both are awesome, accurate, and reliable. i also have several Adams Arms products that have been excellent. on your list you provided, any of those would be great choices, i would buy what's in my budget and rock on

I have always had a hard on for the HK but you can't beat the quality AND price of the PWS.

I have been doing research on what I want as well and will buy a PWS once the funds arrive.

I find the build quality to be top notch. I think there is this weird attraction to the PWS, or atleast thats the way it was for me.

When I went to the gun store to check out the lwrc line and the pws, I found the lwrc rifles to be very beautiful, almost works of art, something just too pretty to get dirty or to put away dirty. I doubt thats the actual case im sure they are great guns. When I got done holding the lwrc IC and m6a2 I asked to hold the mk114... and this rifle just felt like I couldnt ask for more. The balance and weight of the rifle was a lot nicer. Dont get me wrong I will admit the lwrc rifles come with a better lower receiver set up and they look prettier, BUT... the pws just felt right, it felt like that sexy dirty girl that always turned you on, knew what the deal was and what you like, for a lack of better comparison.  

If I were to do it agaon, which I probably will, I will go pws. The deal imo is absolutely impossible to beat for what you get. And some might say otherwise but the pws barrels are matchgrade barrels.

Given the choices above, I would choose the LMT MRP CQB.

I'd go with the PWS. I love mine. I also have the SIG 516 which has been 100% reliable, but the rail is short. I'm holding out until Sig releases the MCX.

I would not go with the HK MR556. It weighs almost 9 lbs out of the box with NOTHING on it. No thank you.

Well its seems the general consensus is the PWS. I will let him know that, does anyone here have any first hand experience with the Barret?

I am a little late to the party, as usual. I just purchased a PWS MK16 and have not had time to fire it. I hope to do so in the next week or two. I went through the same questions and decided on the PWS over the LWRC honestly because the price was so much lower and those who have the PWS love it. After I have a chance to put some rounds through it to determine accuracy and how well I can handle it I will post my findings. I expect it to be 100% reliable, accurate and smooth shooting.

You can not beat the  LMT MRP CQB. Built like a tank and the fit and finish is excellent.

I just bought a .308 POF. Took it out to zero my scope and LOVE it!!!! Not to mention I got it at a great price. It was only $1700 for a $3000 rifle at gotammollc.com. I have read mixed reviews on POF's but after a lot of research I found that the only ones that have had problems were the earlier models. The newer models are AWESOME!!! My wife also has a Adams Arms piston AR and she loves it, but for the price that the POF's are on that site it is a no brainer. Wish we would have come across this before getting her rifle, if we did I would have just got her a POF too...

I guess you missed the thread from 2 weeks ago. Another pof that refused to run.

http://www.ar15.com/forums/t_1_5/1646606_POF_USA_p308_rifle_never_works.html

POS, the most expensive potential paperweight on the planet....

LMT.........

If he's a stickler for fit and finish, PWS is definitely the way to go.  The fit, finish, and machining on their guns is excellent.  But it's the sort of thing that can't be fully appreciated until you examine one up close.

I've read some reports and reviews of their 223 guns, and they are always extremely accurate.  My experiences have been he same.

I'd avoid LWRC.  There just seems to be a lot of drama with the company recently.  Who knows what the factory support is like now or if they will even be around in another year or two.

HighSpeedSteel

I own several LWRCs and have handled and shot PWS and Barrett. The fit and finish on the LWRCs is absolutely top notch. When you put one next to a lower-tier rifle, it is clear just how excellent the fit and finish is. PWS is close, but the LWRC rifles seem a tad better in that respect. Barrett's are very nice with excellent fit and finish as well. But they have not been in the AR game as long as the others and their line is very small, very few different models available. I'm biased, but I would go for LWRC. Plus their customer service is top notch as well.

Highspeedsteel, not trying to be dick but i must disagree. The only recent drama with lwrc is their possible buyout by colt, which didnt go through. I cant see a situation where LWRC just simply disappears nor have I seen a dip in quality since I started following the company back in 2010. And the seldom issues I have seen expressed online were quickly resolved by CS. The only downside I can see to buying a LWRC is cost.

No offense taken Texan38117.  Do you know why the Colt deal didn't go through?  I heard it was because the President or CEO was caught up in some personal legal (criminal) issues.  I have no idea if that's true.  But I heard it from a reasonably reliable source.  If it's true, that's a very bad sign for the company.

Over on m4carbine.net (where they are on top of things AR related), LWRC is thought of pretty poorly.

HighSpeedSteel

According to other information, it was because of the pending lawsuit with F&D, in which LWRCi was awarded legal ownership of the patent in question.

I'm actually happy the deal didn't go through, Colt does a horrible job at innovation and management.

As to m4carbine.net, we are just as on top of things as they are and only heard of a handful of random issues about LWRCi products. Each of them was taken care of by customer service. Every LWRCi rifle owner I've met, both in person has had nothing but positives to say.

Hands down the LWRC M6-IC SPR  the rifle is extremely accurate with follow up shots and quality is second to none..  Barret REC7 would be my second choice.

Im not 100% certain as to why the deal never went down, but if I was forced to guess I would actually venture that it was more of a financial issue with Colt vs drama with LWRC. And yes the owner of F&D is suing LWRC for personal defamation by the CEO of LWRC and also a patent issue with some work that he did with LWRC when he was a contractor working on the REPR with them, To me that is not an issue that the customer base should be concerned about because honestly I think of the owner of F&D to be a complete nut trying to find money where he can. Anyway, however, there is always some type of drama with nearly every company. Trust me, when I worked at LaRue there were personal drama flicks going on that nobody here even had a clue to, but as you know LaRue QC never suffered. You're always going to have an employee loose  a screw from time to time and some random BS is always going to come up. But just like at LaRue, I believe LWRC has a company attitude that is no matter what is going on in our lives we must always be committed to providing our customer with the absolute highest quality product we humanly can. So to me personal issues with even company leaders can hardly put a dent in my perception of the company, what can is the quality of work they put out and furthermore the quality of CS they provide. Both of which, from what I have observed thus far, are absolutely top notch.

As to m4carbine.net, I think that most piston rifles talked about over there tend to have an unfair bias against them. I would look at a Nutnfancy review, or even fondle one at a gunshop for the real story. I don't expect you to necessarily take my word for it, but every encounter I've had with a LWRC rifle I come away extremely impressed.

The ignorant simple minded bias from some on m4c does not make for reliable info. For the most part, if it's not BCM, it's crap according to some old timers there, including one completely closed minded moron moderator. This even after he was corrected by some highly respected guys.

I love m4c, and there is a lot of great convo over there. Sucks that some have bias over there, but I would say the same about some members on arfcom. Definitely some people on here that act as if they are married to the company that makes their rifles and nothing else is good.

I bet you the only reason people can talk trash about lwrc is price, imo. The company has been around quite  some time and they seem to have plenty of happy customers. Cant imagine the rifles not being solid, otherwise they wouldnt be able to charge what they charge. Theres a reason they have a following, they make beautiful and solid rifles. I am pretty sure no matter the top manufacturer in piston rifles, the majority of the praised companies make great rifles. Hold one, pick one and you will love one. Thats pretty much what everyone is saying here.

OP, out of the companies you provided.  I would say LWRC & Barrett.  All of them are good and have pluses and minuses.  The one thing as some others have said is find a shop that carries the brands you are looking at and handle them.  What "fits" one person may not "fit" another.  I personally own a limited edition M6IC and love it.  I narrowed it down between LWRC and HK when I was looking.  The LWRC felt better and lighter to me.  The draw for Barrett is that not many people seem to have them.  I've been looking at then for a .338.  Out of what you have provided it is pretty much down to personal preference.

Agreed. I've owned a lot of different rifles, some were great, a few, not so much. I've owned 4 L'dubs, still have 2 of them. Each one has been flawless. If they were not I sure would not spend the big price for them.

Thanks for all the info fellas, I think he will probably end up with the Barrett. However it will for sure be either the Barrett, the pws, or the LWRC, its nice to know that you really can't make a wrong choice between the three. I have been leaning hard on him to sell his KAC or OBR so he can afford 2 out of the 3 just to be safe, but he doesn't seem to be going for that.