I rode a 50x34 compact last season. When I swapped the 12-xx cass for an 11-xx, wow! Lots more descending speed. It was fun to pedal away from the pack on the downhill. Totally worth it and I don't think you have to sacrifice anything because isn't there an 11x25 cass?! If not, make one by combing two cass and selling the "left over" cass.