I bought a used one. I put the straight trigger and spring kit in it. Also did the right side safety delete. I've only got to shoot it once. It's fun for plinking. If you plan on shooting matches most people say get an AR9. I also bought a few extra mags which were fairly priced. I think it's a keeper.
Bought mine when they first came out a few years ago. Love it! Probably 2-3k through it, mostly suppressed, and no failures. There’s a sh*t ton of aftermarket parts, Magpul now makes mags, so it’s all pretty cheap too.
It’s solid out of the box, but I have done a safety delete, extended charging handle, trigger, trigger springs, grip, HK style handguard, and since mine was a gen 1, had to get a thread adapter.
I have one that I bought as a pistol and SBR’d. It’s been accurate and reliable. The only malfunction I’ve had was with a plated HP reload. Disassembly for cleaning is very simple.
I’ve made some changes with mine. Extended charging handle, lighter trigger spring, grip, SBR stock. I modified the safety selector to be more comfortable. I also added a Trijicon SRS dot optic with an American Defense QD rail mount.
There are some articles on other forums about magazine lips on earlier magazines breaking. YouTube has some videos about some case failures and frame breakages.