When I first acquired the Lensbaby Plastic Optic, I took it to the Missouri Botanical Gardens for a test run. As Rob at 28mmf2 has pointed out, the Plastic is probably the trickiest optic from the Lensbaby stable, but the results (when they work) can be oh-so-worth-it. You should definitely check out what Rob is doing with the Lensbaby in a professional market–amazing work.
These were mostly at f4 or f5.6 if I remember correctly, as the Plastic’s peculiarities are amplified when wide open. All images taken with a Sony a700.