I have used the PI microsensor bib, Bellwether and Falconi bibshorts. The PI and the Falconi are the most comfortable with the edge in quality going to the PI, but for the money, the Falconi were excellent (about 1/3 the price of PI). I ended up buying 4 pair of the Falconi and taking them to RAGBRAI this summer so I didn't have to spend my time washing them.
I forget though where I got the Falconi though. Online somewhere