I've been using this 661 helmet for a few days now, for street riding, and really like it. My commute is 4.5 miles, not that much, so comfort is good. Today's 8 mile fun ride was also comfortable with the helmet not being a hindrance at all.

I am a motorcyclist and wear a full face Arai helmet. Having gone down a couple of times, I realize that I want my jaw/chin protected if/when I fall. A guy at REI told me he's going to get one after seeing his best friend get really messed up in a bike accident, with jaw reconstruction needed.
Anyway, it is nicer than I thought it would be.