Looking for some adive on Giants XTC Alliance 1 or XTC 1

Theres not much in the price between the two bikes. Is the extra money worth it for the allicance 1? Ive listed the differences between the two bikes.
Will the carbon rear end on the alliance give a better ride?

I was also told by a shop that the alliance 1 is alot lighter than the XTC 1 but from Giants website it doesnt seen so. Is this correct?

XtC Alliance 1

*WEIGHT KG / LB 11.40 / 25.02


Weight : WEIGHT KG / LB 11.70 / 25.11

Alliance 1
Frame:Alliance Composite/AluxX
Fork: Fox 32 F100 RL 100mm travel, lockout
Front Mech: Shimano Deore

Frame: AluxX SL aluminium, Fluid Formed
Fork: Rock Shox Reba SL Dual-Air 100mm travel, Motion Control lock out with Poploc
Front Mech: Shimano SLX

Which one would you go for any why?

Thanks in advance.