If you do web development it is also a much better development experience than using Windows.
Bluetooth devices work much better in Linux than Windows (at least the ones I have).
USB devices are also much better handled in Linux. I never see an 'Installing device driver for this USB stick' message.
I plug my kindle in Ubuntu, it opens Calibre. I plug my kindle in Windows, it shows a folder.
I lose all these niceties if I run Linux inside a VM.
Not sure about compatibility with the recent OSX, though. I used lion and mountain lion, and those worked well. AFAIR I’ve used vmware tools from Fusion.
Legally no. VM or not, the real hardware needs to be made by Apple.
In the host machine, you need reasonably fast Intel CPU, hardware-assisted virtualization enabled in BIOS/UEFI, enough RAM, also unofficial VMWare patch to unlock OSX guests on PC hosts.
In the guest OS, you need VMWare tools for OSX, they exist because VMWare supports OSX guests when running on OSX hosts.