I didn't move away from AR's. In fact, I've had at least one AR in my collection for the past 29 years. I did move away from "hobby grade" guns though. I have a BCM and a two Colts. I also have two Arsenal AK's.

The problems I've had with AR's is a long list, and I've been on here too much today so suffice to say:

broken bolt (lost a lug - DPMS)

short stroking (S&W M&P15)

castle nut loosening (not staked - Olympic Arms)

gas key coming off (not staked - Bushmaster)

screwed on gas block working loose (ArmaLite)

trigger guard falling off (the pin worked out of the lower - Rock River Arms)

broken hammer (broke clean off - DPMS)

sheared off buffer retainer pin (bound up gun - SGW)

broken extractor (high round count gun I bought used from a Police Officer - Bushmaster)

frozen selector (this was on a Colt, but I caused the problem when I changed out the Pistol Grip)

sticky chamber (S&W M&P15 - Smith deburred the chamber at the factory after I sent it in the second time)

That's a short list. Remember, I've owned AR's since 1984 and use to shoot about 500 rounds a week through them.