For years I have thought I wanted a nickel boron coated BCG. I have never pulled the trigger on one. I am starting to feel the need to tinker with my AR. What do folks think of these? Who makes the best one? Or is chrome a better option? If chrome, who makes the best one?

A NiB BCG is fine. As far as quality is concerned, you will find that it varies. Of course, price has a lot to do with it. I have spent as little as $99.95 for an AIM Surplus NiB BCG to $190 for a WMD NiB BCG to $280 for a LANTAC E-BCG. The WMD and the LANTAC are the best I have ever used. The AIM Surplus is just fine. It did discolor just slightly, but the coating has stayed intact. A chrome BCG is fine, but you are limited. Not that many choices are available these days. You really need to decide just how much you are willing to spend for a NiB BCG. If you want really good quality, it will cost you.

PA has Failzero groups for $100 every year it seems.  Toolcraft NiB is done by UCT which is Failzero and every bit as good as WMD..these run $115.

OP my conclusion is all the types do their job well. It's kind of a wash IMO.

What do folks think of aero precision? They are local, and I would like to support them if they are any good. I am looking to spend about $200.

Seems to get favorable and not so favorable reviews. Here are a few from Primary Arms' website.

Aero Precision NiB BCG

My WMD NiB BCG flaked and stained in less than 500 rounds.

My chrome BCG looked brand new the day I sold it, after 4000 rounds.  

I buy nitride QPQ now.

I went chrome long before NiB and QpQ came out. I have never used NiBo BCG's so can't comment on it personally. There have been threads here about carbon freeze / stick with NiB BCG's, FWIW.

This right here.

My first BCG was NiB and it was getting stained as soon as I start shooting with it. Then I start buying nice chrome BCG and it ran just as good without the stain/flaking. Nitride BCG is my favorite. 

My NiB (WMD) has 6kish round through it and is heavily stained. Doesn't bother me though as it rides very smoothly. My chrome (Young's) has about 3k through it and looks new. It is not as smooth in the upper as the NiB. If I had to do it again, it would be NiB.

Do you have a problem with your current BCG? Why do you want to spend 200 on a new one? Is there something else that would benefit you more?

I have a psa premium NIB bcg and it has no staining after over a year. Not the only rifle I shoot by any means but it looks brand new.

But I wouldn't buy one just to buy one.  It was a good deal at the time.  Since then I have bought about 5 or 6 phosphate bcgs.  I don't know that one is any better than the other.   Photplate need more lube, but they also retain lube better because they are porous.  So really not sure if any are better than the other.   I wouldn't buy a boutique bcg, tool craft or psa is g2g.

I got 4 psa premium bcgs for 79 shipped each, I'd rather have that than 1 $300 Lantac bcg lol

Chrome by all means!!

Any experience with FailZero BCGs? Do they tend to stain also?

Yes

+1

there is a reason this is still the military standard.

Running 4 aim NiB $99 BCG's and have no complaints, they do tend to darken up a bit and stain if you soak some solvents on them but they are 100% functional.

I also have two AIM NiBs, first one has been in my BCM upper for 2k rounds. Some slight discoloration but no signs of chipping & wear.

I think it's still early to see how NiB will hold up long term but although there's some occasional reports of chipping that doesn't make NiB a fail.

Overall, who makes your BCG is more important than coating. I've had quite a few phosphate carriers run fine in multiple rifles for many many rounds.

I could care less about discoloration, I didn't buy a NiB BCG cause it's pretty.

I think the staining looks good personally

Anyone running one of these: DD chrome BCG ? Is it MPT tested?
How about this one? BCM IB FDE What is the ion bonded coating made out of? I assume that is what IB stands for...

I have 3 different BCG's

plain BCG I got for free with my CBC upper.
It works fine, only about 500 rounds on it though

NIB I got this from a local gun shop
honestly it's nicer to look at than the nitride one  but I don't think it's better
it's not really easier to clean other than I can tell where the crap is on it. (you can get these for $100, the $195 is MSRP)
I'm not any more impressed with it than the nitride one, it just looks better.

chrome
this is my favorite one, super easy to clean and looks great, granted it doesn't get very dirty with the piston system.

my brother has a chrome RRA bolt in one of his DI AR's and it wipes right clean just like my Ruger one.
the RRA is $170 list price but can be had for $130 to $150 from dealers (RRA had them for black friday for $125)
RRA Chrome
I'll go chrome from now on

Never had an issue with my NiB bcg's on suppressed SBR's.  They run dirty, dry, clean, wet.

No chipping, peeling or other problems with my WMD Guns NiB-X BCG at about 3,000 rounds now.  It has slowly, ever so slowly developed a generalized patina that is softer and less shiny, but not actual staining.  I don't run suppressed, however.   It is my opinion of one that NiB is a fairly complex plating process and probably is best done by companies that have a long history of industrial nickel- boron plating.  The parent or sibling companies for both Fail Zero and WMD Guns have that long history.  You might pay a little more, but it's worth it.

You can go to Fail Zero's web site and find a link to a pretty extreme torture test done by a third party where then ran their BCG in military M4s in dirt, sand, water and other extreme conditions compared to Milspec in three different rifles, running until stoppages occurred.   The results were pretty impressive.  That played a role in my decision to go nickel-boron, although I ended up choosing WMD.

Here you go, the link is to a downloadable PDF detailed report:

Fail Zero Full Auto Test to Stoppage versus Mil Spec BCG