I have just made the switch to the Mac (a Macbook Pro) and I am well impressed. I am running Windows via VMWare for applications that I will find 'handy' for work purposes.
I am only frustrated by my lack of knowledge about the Mac OS - but I will learn...
In very general terms, I do not regret for one minute moving to the Mac. It's a great piece of hardware, and it does not run hot at all.