I’ve got a carbon reaction and I love it. Its very stiff, direct, accelerates easily and carries the speed. It climbs really well (for me) which is my weakest area of riding and hence is probably my fastest overall bike. With regard to strength, I am about 108kg and am pretty hard on my kit usually, but having ridden it more as a trail bike, rather than for pure XC, I have not had any problems with it, despite clattering through wrong lines. Because it is so stiff, you always know when you have ridden it as there is a bit of dull back ache, but it’s worth it for the sensation of speed and how quick it covers the ground compared to my other bikes, for which you sacrifice some comfort. You won’t be disappointed, if you want an responsive, racy ride.