The one thing you don't mention though is the exact opposite side of the equation. The downhill. I could easily see the need for some darn good brakes or your going to blow your legs to pieces if you are riding in the hills/mountains on a FG bike. You have the lower gear for climbing and then the same low gear is trying to force you to spin at insane rpms coming down the mountain. It's not as bad in the summer months as it is in the winter months since you can easily ride a higher gear in the summer months and get away with it.

It would be interesting to try and see how much I could cuss myself out for being crazy enough to try it. I saw someone this summer that was riding one of the two. I didn't know enough at the time to pay attention to be able to recoginize if he was on FG or SS. I wasn't quite prepared to see anyone even out riding either or...unless it was at a track somewhere, but I guess he does it all the time.