I wear PI AmFib tights, albeit not the bib version. I've worn them comfortably down to 10 degrees F, but just mountain biking on snowmobile trails. I don't know how low you could go on the road when you throw in a 25-mile-an-hour wind chill factor. On the upper end, they get too warm when the temperature reaches 50 degrees (road riding).
As for durability, they seem fine. Have crashed into crust several times, not a mark. Haven't test-crashed them on pavement, though.
Mine do not have a chamois, so I wear padded shorts underneath.
Last edited by Rod Arnold; 02-21-08 at 07:01 AM.
Reason: Didn't answer all the questions