I have both hydro and mech disc brakes. I only have the hydro cause they came with the rig, if i were to have to pay i would use mech disc brakes, but GET the dicer avid witht eh brake adjuster. the hydro's are crisper but maintanace is a pain. i ride on frozen snowmobile trails in maine and bever have freezing issues, but i truly like the avid mechs better. they both put enormous pressure on the disc, and brake better than any v-brake style brake I've had. The hydro has a crisper feel for sure, but just not worth the ha$$le.

Now if somebody would design hydro shifter.... then we'd be talkin'.