i rode single speed for a long time before switching to fixed a year ago. in short, i'm now twice the biker i was before (through necessity without brakes, i learned to make better/more calculated decisions in traffic and use my energy way more efficiently) and always feel like i have absolute control over my bike. when i ride my road bike now, i can go fast and everything but i feel completely disconnected and can't even remotely flow through traffic the way i can on my fixed gear.