The light weight/thin fleece inner lining is just enough to keep the legs a little warmer on cool weather or rainy rides but not bulky or overly hot.
They have worked out great for long rides in the mountains with the big temperature swings. They work well from temps in the 40's to 90F, not many complaints about them at either end of the temp scale. Pretty much the only bibs I have ever owned that can do that.
The Cirro OF pad is nice, complies with the body and not bulky as with the older pads but with the comfort taken up a notch.