The problem with dual-booting Windows is the inconvenience of having to restart your Mac entirely. The problem with virtualizing Windows is that it can be unreasonably slow for a prolonged session. Now that Boot Camp and Parallels work together, you can choose between virtualizing or booting into your Windows depending on what you have to do.
No restarting to use Bootcamp. Just select “Switch to Windows” from OS X, and your machine goes to sleep. Wake it up and your in Windows. You can do the same thing once in Windows to switch back to mac. VERY VERY NICE feature, no reason to use virtualization for me at least.
