Looking into a nickel boron BCG and was wondering what experience other shooters have with them and which one is best, Spikes, WMD, Fail Zero, etc?

I have one that I got from AIM surplus. It works (I had to remove the o-ring from the extractor for it to do so) and it's easier to clean than a phosphated bcg, but other than that...meh; still needs to be lubed just like any other bcg.

get this

I, also, use the Aim Nib (budget $99 version) ones. They have worked well for me as is. As noted, they do clean up easier, although tend to tarnish VERY quickly (blacken) in case that bothers you. The tarnishing does not seem to affect the Nib's properties.

WMD is serving me well.  Excellent build quality. Cleaning means just wipe it off.  Only about 1,500 rounds on it but still looks new.

I have 1 fail zero.  It is a good bcg.  But as I have stated in several other threads, I will never again pay a premium for an NIB or other coated bcg.  I have several quality bcgs from Spikes to BCM, they work just fine.  I didn't think the cleaning was easy enough to warrant a premium, even though it is a bit easier to clean.  Problem is I always clean my stuff when I am done, so cleanup is generally easy to begin with.  We all like different things and the Fail Zero has served me well.  

personally I hate cleaning (ex military) our armorers were white glove armorers and they loved being jack@sses.  I have a failzero and a polished WMD. the WMD cleans up a little easier.  also after a few hundred rounds my cam pin on the failzero is pitting.  I do a quick wipe down of my bolts after each fire session