Well in terms of fes that support rotation natively you have gl, 3darcade and emutron. That's literally it.
Now you can add to that list with video card that supports hardware rotation to virtually any windows fe.
Software rotation programs aren't worth it as they are very very slow on even the best of systems.
(On an unrelated note, this was a good question. "What's the best?" questions are only vaild when you are very specific in what you want.)