Cranks:
I’ve always run Shimano but…
I broke an SLX (9spd) crank earlier this year.
One of our group broke an SLX (10spd) crank yesterday.
My new bike has SRAM X01 11 spd carbon cranks and they seem quite tough. Shame about the GXP BB longevity (lack of) though. I’ve packed it with waterpump grease from new but will go Hope when it fails.
Cassettes:
XT 9 and 10 spd has always worked well for me but X01 11 spd is even better. Shame they cost so much though. Will probably go GX when it comes to replacement time.
Rear mechs:
XT 10 spd & Saint 9 spd have been the most reliable to date for me but the X01 is holding up really well so far. Two big rock strikes on the mech in the last two rides and it’s only scratched it. They do seem to stick out in harm’s way a bit too much though.
The deal breaker will be the cost of a new X01 mech though. Mech’s are consumable items IME. £40 for an XT is tolerable but I’m not buying 2 or 3 X01 mechs every year!!!
I think the 11 spd config will end up as XT mech and shifter, SRAM cranks and cassette, Hope BB.