Upload & Sell: On
outdoor swimwear shoots at the beach? Unless you are talking about candid/ voyeuristic type South Beach shots from a long distance, I wouldn't think either lens would be the choice. Maybe more detail of what and how you are shooting might help.
FWIW, I have the 200 2.0 and the 300 2.8 IS v.1 and I think that the 200 2.0 is a faster focusing, sharper, better built lens. Considering that I thought my 300 2.8 IS was my best lens until I got the 200 should tell you how good the 200 is.
If you are shooting swimwear, you are looking for full body and decent DOF (I would assume) which would mean that a 200 2.0 or 300 2.8 are too long and too fast for your needs...You would be paying for something that you don't need. Get a 50mm, 85mm or some other prime for a fraction of the price.
Maybe I am misunderstanding your use.
Best of luck,