I’m afraid I’m with the OP.
New it was sweet, beautiful group set, I didn’t know how much I missed the way SRAM gears bang down.
Within a few short, summer months it was ghost shifting, stuttering, lagging and generally being a sod. I changed the chain even though it really wasn’t worn and The cable which only helped so much. I’ve got the B screw guide and spent hours indexing it.
My mate’s was worse, on inspection then rivets that hold the mech together had quite a bit of slop in them, a new mech fixed his problems, but I’m not in the mood to replace mechs every 3 months to keep it running sweet.
I’ve decided that 12sp is just too much for something thst takes the sort of treatment that MTBs get, maybe a wider cassette with gaps more like 10sp would allow a bit more tolerance.
I’m going to keep an eye on how 12sp XT goes for other riders, I’ve got DT hubs so it’s a pretty easy conversion, but I’m tempted to go back to 11sp I’ll miss the big 50 winch gear, but I might live with it.