I've a custom AM831 and I've totalized more than 300 km on it, including a couple of bike parks. So it's "only" 300 km but the bike has been well tested.
About the flex issue: the problem was there, even if in my frame probably the bearings weren't pushed out of the recesses so it wasn't that bad; after I made the JJJ brilliant fix the rear is much more stiff, still I don't know if a brand bike is more stiff; I think after the mod the bike is ok.
Generally I love the bike, I assembled it trying to keep it light, it's around 12.6 Kg, a record for a 160/150 mm dual suspension; it pedals uphill very well, also I found very useful the DT swiss rear shock that has three positions: open, pedal and locked; the middle position is fantastic to use uphill.
Downhill it's great, it's very fast on the flow, fiddly to jump as probably all of this modern geometry bikes, they are big like aircraft carriers
.
Problems: to me press fit bottom bracket is a very,very bad idea, especially on a carbon frame;said this the original bottom bracket was almost locked, bearing destroyed from water; anyway I managed to push it out and replace with a shimano XT. I also have quite a lot of pedal strikes this is my fault as I bought 175 mm cranks, 165 , max 170 would be ideal.
The biggest headache came from manitou mezzer fork that wasn't plush on small bumps, now it's 90% solved after I replaced the damper oil with the lightest I could find.
The bike is fun but I don't trust the frame 100%: all carbon parts (even brand ones) can fail, the knockoff probably have a higher failure rate; anybody that see any crack on the frame please report.
I don't have any squeaks from suspension so far.