No gears(less maintenance, less to go wrong), easier to carry (especially up stairs and especially for smaller people - my girlfriend couldn't lift her mountain bike but can lift her fuji easily) and significantly lighter compared even to a new road bike especially in terms of rear balance. I found they build my legs up quite quickly to the point where any worries about moving to a compact group set completely disappeared.

Plus they are just fun. They have a different feel to my road bike, you just spin and go.
(skgorsky, Tue 4 Oct 2011, 13:48, 2 replies)

Should add that I run brakes on mine. The no brakes thing is insanity.
(skgorsky, Tue 4 Oct 2011, 14:37, closed)

All your arguments justify a single speed, but not a fixed gear.
Averaged sized and rides an old racer refitted as a flat-bar commuter, since you ask. I also laugh at people who commute on MTBs (except PJM, coz he's scary).
( CQ Knows the truth, all of it., Tue 4 Oct 2011, 16:49, closed)

I alternate modes using a flipflop hub because I'm cool like that.
(skgorsky, Wed 5 Oct 2011, 10:43, closed)