i disagree with dutret and think using the FG as training (especially the resistance part) has made my legs a TON stronger.

part of the allure of fixed gear for me is you get a workout up AND downhill (otherwise, your right, why not just use a coastie bike).

with time your legs will get stronger and resisting will come easier. just take it easy don't overdue it at first (or you might experience the famous exploding knee thing everyone talks about). with time and practice you'll see you can resist well enough to stop yourself from almost anything. just use your legs till they are tired then switch to the brakes.

i have a big steep hill that t's directly into a stop sign on my daily commute. at first it was terrifying and i couldn't imagine hitting it without brakes. now, after riding fixed consistantly for maybe a year, i honestly can't telly you the last time i used my brake bombing it. it is really fun to try to contol the pace on the way down then come to a big skipping/skidding stop at the end so i don't get killed in traffic.

i do blow through tires at an alarming rate though...