Cons of bibs:

They can chafe your nipples if you don't wear an undershirt.

When you find the size that fits well around the waist, the suspenders might be too short for you, and pull on your shoulders.

You may have awkwardly-shaped shoulders like me, causing some suspenders to keep sliding off and need re-adjustment.

An extra pair of bib shorts in your pannier is more bulky than a pair of bib-less shorts, plus there is more material to wash and dry.

Shorts are cooler in very hot conditions (even Assos sell a pair of bib-less shorts that they recommend for "hot summer" conditions).

With some brands, shorts can be a little cheaper than bibs, but this is not always the case.

Bathroom stops can be a real pain when wearing bibs.


Cons of shorts:

Overweight people say they don't stay up so well (but I cannot comment on this myself, I'm not overweight so have no problem with shorts).

Don't buy the Assos shorts - they are the only ones in the world that are not comfortable for me - the pad sits in the wrong place, and the lack of elastic on the front is an odd, useless feature (Assos bibs may be awesome, but their men's shorts model sucks, altough my wife tells me that their female shorts are great).