if i'm doing any kind of serious ride it's all i wear. i also find you pretty much get what you pay for. Castelli, Bergamo/Capoforma, Craft, Giordana, Descente all make nice bibs. If you want the best though, theres only one: Assos.
Bibs are like many other pieces of high end gear, you never knew you needed it till you tried it. (Chamois creme falls into the same category)