Maya works fine in Bootcamp, I've done quite a bit with it so far, but as far as rendering goes, it'll always be an issue as long as you just have one computer. Rendering, like anything takes a butt load of time, depending on how much you accomplish with Maya and unless you have 12 or 13 quad core computers all hooked up to one another, it's going to take awhile to render something with an Apple using Bootcamp.
Reguarding Maya on Mac, I would highly suggest you find a way to use Maya on the Bootcamp side. From my experiences, when you use Maya on the Mac side, switch the file to the Windows side, and then modify it on the Windows side, the file will not work on the Mac. I think it has to do with how the different functions of the Mac and Windows operating systems work, but I'm not 100% sure.