I've been riding my xx1 for about it week. Works as advertised.
I've been able to climb everything with the 32t. The extra torque makes makes getting over wet roots a bit more tricky, but that might just be a practice thing.
I may get a 28t for the Chilcotins since the altitude is pretty rough.
The shifter isn't as fancy as the shimano xtr setup. Only one click to go down the cogs.. and 5? to go up. The paddle to go down only clicks in one direction (vs the xtr where you can use your thumb or index and moves 2 gears).
I definitely prefer the installation for the xtr cranks over the xx1 setup with the preload adjuster, bb end caps and all that garbage (preload only on pb30, bb30 version).
There are no bash rings available unless you swap spiders (ns billet). You could go taco style.
The pulleys on the derailleur are keyed like the chain ring is. When removing the wheel, sometimes the chain can move out of order, requiring you to mess around for a bit to get it back in line.
Overall, happy with the setup.