When I got my first ssfg bike, I was sure that I would only ride it as a single speed. I couldn't understand the desire to ride fixed. I tried it and the challenge of it made me stick with it until I felt really comfortable. I recently tried to switch it back and the first time I went to back pedal, I felt an instant of utter panic, like the drivetrain had somehow broken something. It felt totally out of control. I've ridden fixed since then. There's an amazing rhythm that develops in your cadence. I find that I ride faster and more efficiently. I still run a brake though. Hills and no brakes scare me.