At Rawles' Survival Blog: Two Letters Re: No-Name AR-15s.
Mostly noteworthy (to me) for the discussion of points of failure, and recommended spare parts and tools.
Mine is what is sometimes called a "FrankenAR": I bought the upper off of a guy from the (now sadly diminished) WA Hometown Forum on AR15.com, and assembled the lower from a WAHTF lower and parts purchased at gun shows. So far, so good, but I probably haven't even put 500 rounds through it.
As with just about any semi-auto, magazines are a serious point of failure. I have a bunch of GI 30 rounders that magically appeared in a duffel bag in the garage one day; I've replaced all the springs, and tossed the original issue followers with Magpul's anti-tilt numbers. I have a couple of GI 20 rounders, as well; since the mag body is straight, not curved, they don't need the new followers. (The curved 30 round mags with original followers have historically had problems. The anti-tile followers essentially have longer legs that prevent them.)
I also have half a dozen "windowed" Magpul P-Mags. P-Mags are cheap enough, and good enough, that I see no particular reason that someone wanting to build up a healthy supply shouldn't just go with them.
BTW, I always used a 20 round mag while in the field during my Army career; it kept grunge out of my rifle as well as a 30-rounder, was a bit less unwieldy, and was distinctive enough to make ID-ing my rifle in a stack or rack a bit easier.