Consider that Hans Zimmer uses Cubase on a PC. And it’s not like he can’t afford a mac. The truth is, a PC will run Cubase much more efficiently, given the same processor, RAM etc. So, with $2,000 you can build the ultimate PC that will be faster than anything Apple has in its catalog.
Windows 7/8 is extremely stable and reliable. You won’t lose anything by switching, only gain.