Oh how silly!  I have a Mac Pro 8 core with Mac OS (obviously) and Win Vista Business 64-bit on a separate 250Gb HD.

Best hardware/OS for the $$$, and the best Vista platform!  I render Vue scenes on the Vista side, as Vue is about 40% faster than the Mac version (32-bit only), and uses my 10 Gb of RAM nicely. I do prefer the Mac's wonderfull OS, but I prefer the 40% reduction in render times even more.

Just run Bootcamp, and trueSpace will work fine on your Mac! ; )  To me, the Mac vs. PC debate is over, and such debates are a waste of Intel CPU clock cycles.