I rode the Bike MS Bay to Bay Tour this past weekend, and there were a couple of dudes with fixed gears that rode the century challenge (108 miles), one ofthem finished in just over 6 hours, hills and all. Pretty intense.
For those wondering, the Bay to Bay tour is a ride from Irvine, CA to San Diego, CA over the course of two days. There was an option of 150 miles, 100 miles,50 miles, or 30 miles. I rode 100 miles total, 58 on day 1, 42 on day 2. I broke a spoke on my rear wheel 45 miles in on Day 1 coming out of Camp Pendleton,got it fixed, and then broke another spoke on my rear wheel 17 miles in on Day 2. The wheel wasn't so out of true that I couldn't keep riding, but itwas annoying.
I talked to the dude riding the fixed gear at one of the rest stops and he got me interested in it, but I'm not sure if I'd want a free coasting hub ornot. He pedaled for all 108 miles, it just seems like a lot of work, especially to average 18 MPH the entire time. I love to coast down hills...