Deore XT was the first Shimano groupset to get the new Shadow rear mech design, which does away with the top spring for reduced clatter, has a narrower profile to avoid crash damage and incorporates direct cable routing so there are no big loops of cable to deal with.
Ball bearing internals and instant cable release make XT shifters fast-acting, smooth and reliable. We’re big fans of Shimano’s two-way release design, which allows the release lever to be flicked backwards with a finger or pushed upwards by a thumb.
If you’re standing up to climb, the finger option works well. But if you’re hanging off the back going downhill, then being able to use your thumb instead is a boon. The shifters also have neat gear displays that can be easily removed if you don’t want them – take them off and you’ll find a replacement cover for the top of the shifter tucked inside.