Looked at a shop with 8-10 brands of lower receivers stripped for sale.  All looked the same but for the silly nickle colored one.  Prices ran sub $100 for something I never heard of before to $250 for a Novaeski who I thought made rifles for sale.  I guess all of them are reduced to selling lower receivers now for a buck.  I guess hearing the fancy names means nothing any more as it could be a factory rifle or a stripped receiver.

Major difference in how well they are roll stamped with names and markings.  Some are neat and business like, such as DPMS and Armilite.  Some others looked like a kid with an ice pick did it before the anodizing went on.  Rock River and Bushmaster looked normal.

I can remember Armilite, DPMS, Novaeski, S&W, Rock River, Spike, Stag, Bushmaster, Double Star?, the nickle chrome no friction one whose name I forget, and a couple others including something with LCWI in big (ugly) letters with maybe LMT on it also.

Is there any real difference in these things?

One of the brands was marked (X) for no bullet, (0) for one bullet, and (000) for full auto.  I didn't know you could buy an auto receiver for $150.  What's that all about?

Which is the best just to build a pop can buster from?

As long as they are in spec. they are good to go weather they are $69 or $250.  A lot of them come from the same place.....just with different markings.

It's the parts that go inside the receiver that make in FA, not the receiver itself (as long as it's machined for the FA parts).

Get which ever one you like best based on the amount of money you want to spend.

1st post has it.

After that it's brand loyalty, which is as big in the AR world as anywhere else.

Nah.

Most differences in stripped lowers are minor & cosmetic, and do not affect the functionality of the finished weapon. There are some exceptions, and some lowers are made with more care & craftsmanship than others. The magazine well in particular...you want your empty magazines to "drop free" of the weapon (this is also a characteristic of individual magazines i.e. some drop, some don't).
Look for the things that matter to you: price, availability, finish, brand recognition, and resale value are common considerations.  
http://www.ar15.com/forums/topic.html?b=3&f=12&t=318113
From the list you gave, Spikes would be fine for a "pop can buster" (or whichever is cheapest).

Another difference is some lowers like Superior Arms and AGP Arms come with built in set screw to remve trigger pre-travel for a nice clean break with standard trigger. No premium price for those lowers and you don't have to use the added feature if you don't want to but makes a big difference over the typical long creepy pull of standard triggers in non-adjustable lowers..

I have seen some difference in the cheaper lowers with the fit and finish, such as tool marks and rough around the edges. Also the finish is better on some brands such as Mega, for example I had an upper that the finish wore off pretty quick in the high use areas but i wont name names because i like the company. As with most thing you get what you pay for, but you never get what you don't pay for

Just go to Spikes tactical they are always having sales on lowers.

like some said befor as long as there in spec they are all the same...   the rest boils down to preferance... like for example... preferred brand or company...  finish and logo are some of the most differances...  some will have a less desarible finish on them, and some will go all out on the finish...
there is one thing that i look for in a lower reciever that i feel is an improvement in function...  THAT IS THE MAGIZINE WELL..!!!   for example; the first lower i ever bought was a rock river (for the name) of course...   but my second lower was a   JD MACHINE   what i like to call my "JD Tactical"  and that was almost half the price of the Rock River
and in my opinion, it is alot better, because of the Magazine well....   on the "JD tactical"  the mag well is Flared out, way more significantly than that of  the Rock River and for this reason, to me, it makes it better, becuase it really assist me in faster magazine changes and That " TO ME" makes the JD a better lower, and the roll stamp is really cool looking too.. it has a Tactical Cross hair that i like to paint in white to make it stand out... but this reciever is also stamped in MULTI CAL  witch is nice in case you want to build a rifle in a differant Cartridge other than 5.56/.223 like a 6.8 or 6.5 or even a 7.62 x 39 or even 5.45x39  with a Multi Cal stamp, it makes it a nice option...  although the recievers stamped 5.56/.223 will work for any other caliber. "In my opinion" id rather not have a rifle chambered for a differant caliber and stamped wronge...  so that is something to consider...  
However on the JD reciever, although i like the stamp and logo and especialy the Mag Well..  I DO NOT like the finish... its ok and for the money i love them, but im not found of the reciever FINISH...   i do like the Finish on a Reciever i have that is LRB  ARMS  and i love that it is stamped "U.S. Rifle" and the stamping is really deep and you can tell the quality and of this reciever and that it is really good... but the mag well is normal, and not flared out like the JD.. soo like i said befor...  it just boils down to preferance...  and probably how you are going to run your rifle, and or what you are going to be using it for...  For example if you going to be building a rifle for accuracy, than i would look for one that is machined really tight to the upper reciever that you will be using, and even try and get a them both togather and match fitted... a tight magazine well with minimal flaring, would be prefered as well for accuracy work, so that there is less movement in the magazine from shot to shot..  but a rifle for Close Quater fast drills, or run and gun with alot of fast magazine changes... look into something like the JD with something that would allow for faster magazine changes...  

and this is all just my opinion or view of this sub.. ..   hope this helps a little...

I prefer AGP besides the trigger preset screw (which you can aces while the rifle is assembled), they wire edm the mag well every mag i have ever tried has dropped free and goes in smooth features/price they are the best in the industry for forged lowers.   Also they are local for me.

AR Lower Receiver FAQ (56K Beware) MMS, CMT, LAR, LMT, Compared... - tacked thread link


Here you go, just pick the features that you like at the lowest price possible.

For myself the main thing I look for is that the mag well would drop free the mag specially the Magpul PMAG which is my favorite, second would be the markings and third the manufacturer's overall quality.

main thing I look for is that the mag well would drop free the mag specially the Magpul PMAG

AR3,  Interesting you mention this.  I bought one of the lowers and every 20 round or 30 round metal magazine I have tried, Colt, OKay, NMHTG, CProducts, Adventure Line, slide in easily and fall out without interference from the stripped receiver.

BUT the MagPul MagLevel I tried is a push fit in and a pull fit out.  It goes in and would lock, but is a friction fit, and fully loaded won't budge by its own weight.

The mag is not the same size as the metal mags when I measure it with a caliper.  The mag is way out of spec.  Both front to rear and side to side.

Not really a problem since I use the metal mags, but MagPul isn't drop free.

In fairness, I tried the MapPul in other receivers and it is a looser fit but barely drop free, if at all, in some.  In others, it will not drop free even fully loaded, but it slides in and out easier.

It doesn't matter much to me anyhow, because three MagPuls will not fit into a 3x30 mag pouch anyhow.

Some of the expensive ones are machined from a billet of aluminum, instead of the cheaper forging.  Plenty of debate on whether a billet lower is 'better,' but since the lower contributes little to the accuracy of an AR, the difference is mostly just fit and finish, and it all comes down to what you as the buyer thinks looks best, and are willing to pay for.





The ones with the full-auto marking are called 'low-shelf' receivers, meaning that they won't need modification should you decide to buy a full-auto parts kit for them.  If you have a semi-auto only FCG, then you won't be able to put the selector switch on the full-auto setting.  It will just be cosmetic.
 

Well, since you won't be using any PMAG you won't have any problems even if you picked a lower with a tight mag well.

Like I said lowers have different size mag wells, some are close to the minimum size and I'm sure there are some out of spec out there that's too small.

My LMT lower have a tighter than normal mag well, out of my 20 PMAGs only about a couple of them didn't drop free at first, but after using them several times they now drop free, this is the opposite of my three Colt lowers, one is a Match Target HBAR and two are 6721 tactical carbine, all my PMAGs drops free even when new.

I prefer my PMAGs over my USGI 30 rounds aluminum mags which some I've been using for about three decades now, I dropped two PMAG fully loaded, five feet on concrete garage floor, feed lips first (without any top covers) and no functional damage, I even accidentally stepped on one at one time and no damage.

Also I like that I could actually load it with 30 rounds while my USGI mags I usually download it down to 28 rounds so they're easier to load on a closed bolt.

I like the 6 MagLevel PMags I have.  They work perfectly as far as firing.  They are just hard to carry since they don't fit into normal 3x30 pouches.  The top cover protects them while loaded and they work really well for a spare to bounce around loaded in a pocket or gear bag.

The same could be said for the metal magazines as well.  They work.  But fit and drop free in anything.

If I am worrying about a MagLevel not falling out, it means I have burned the 19 in the gun in a straight 20, the 28 in the MagLevel I reloaded with, and am now worried about a second reload.  Not.

No longer having the slightest interest in the squad in the attack phase, I think the 19 in the first magazine will do just fine for Escape and Evade.  E&E gets confused if you are shooting.