I have purchased a couple of Ultimate Upper kits. I've also gotten some friends to buy.
Its a solid deal on good stuff. The lighter PredatAR barrel on the rifle I have starts walking after 10 rounds or so.
I've shot it from rest only once, but here were my results.
1) 55 GR lake city - 4 moa
2) 62 GR green tips - 2.5 - 3 MOA
3) 69 gr SMK precision reloads (made on a single stage as opposed to cranked out on my Dillon) - 1.5 moa.
I write this with the caveat that the optic on the gun was only a 1-4. I'm confident if I really worked on my NPOA and used a 12X or more scope, I could do better than 1 MOA with my reloads.
Also, my groups are the average of multiple 5 shots groups. These are not cherry picked 3 shot groups. By that measure, the groups would be much smaller.
I have had zero malfunctions with my rifles and neither have my friends. I have somewhere between 600 and 700 rounds through mine.