I'm a HUGE fan of bibs, however I only wear them if I'm going to wear a full-zip jersey with them. Having to pull a jersey over my head with all the stuff in my pockets is a PITA. I can just imagine me dropping my cell, wallet, and GU flask in a porta-potty or something. With full-zip, you just unzip and take it off -- no pulling over the head.

Some women don't like bibs because the "bib" is too long for their short torso. I recommend a women's specific bib if possible for just this reason.

I also recommend wearing a light base layer under the bib (will prevent chafing from the straps).

Oh, and I've got a friend who got creative, cut the "bibs" at the shoulder and put velcro on them so she could just un-velcro and pull the straps down without removing her jersey. Cool idea, but she has to have someone else re-velcro them for her when she pulls them back up.