If you have - or believe you have - a less than perfect body, then this must be a no-brainer. The bikini is the most unforgiving of garments. It's designed to reveal more than it conceals, and that makes it most women's worst nightmare.
I would argue that it's not really a garment all. At it's most basic, it's bits of string with triangles of fabric attached. Bikinis are pretty standard really, when you think about it.
There's not much to fire the imagination from a design perspective. You can change the fabric all you want and vary the amount of fabric involved, but in the end it still amounts to the rough equivalent of a bra and pants that you wear to the beach.
The swimsuit, on the other hand, gives far more coverage, you can choose one that reveals the bits that you like, while covering the bits that you don't. You can hidden support for sagging tits or bulging bellies or drooping bums.
There's also more of range to choose from: halter neck backless items, scooped, cutout, deep v-ed. They can be sexy or demure, brash or subtle. It's you choice which means that you can create you own comfort level.
The good thing about a bikini is that it is probably the one item of clothing left (apart from underwear) where "looking good" does not automatically equal "stick thin". All those stickie-out ribs and pancake flat tits and arse don't work in a bikini.
To truly look good in a bikini you have to have curves in all the right places. You gotta have booty. Just look at Bond girls like Ursula Andress or Halle Berry or take a gander at the girls on the beaches of Brazil or Miami. Now compare that with your common or garden variety size zero and tell me which looks better.
Conversely, the wrong swimsuit can quickly descend into the mimsy and mundane. Remember those pics of Uma Thurman in her plain one-piece on the beach? Before that picture she was a universally acknowledged hottie, after it she lost some of that heat.
So what am I getting at? I'm saying with this one there's just no clear winner. What really matters is being sufficiently confident in your body-shape to choose the right swimwear for you and then letting everyone know how gorgeous you think you are.
See:
Five of the best... swimsuits
Five of best... Bikinis