I rode single speed for about a year and yeah, it was inadequate for my commute: it lacked both the top speed needed for my morning home run along 1st ave and on a hard day it was too much to press up the bridges' ramps. Then I had a 4 speed IGH and that was quite adequate until it died. Then I figured I'm gonna stop screwing around and went back to the traditional derailleur and never looked back.