Calvinandhobbs:The "vest" is the only BC I've used so far. I've been reading about bp/wings and the mechanical engineer in my couldn't help but wonder if it is possible to get the best of both (less drag, but no tipping problem).
A BP/wing does not have less drag. Drag is reduced by making the BC more streamlined. Some BP/wings are streamlined, others are not. The same goes for vests, although streamlined vests are getting harder to find.
Things on a BC that create drag are padding (yes, I see padding on some BP/wings and most vests), cummerbunds (also found on some BP/wings and most vests) and a double bladder design (fabric covering over the bladder - often found on wings, not as common on vests these days).
None of these drag creators have to be on any BC. They are there because you've been sold a bill of goods and will pay extra for "features" that make a BC more difficult to use.