Dualbooting will give a better performance (by a lot). However, virtualization will allow you to run both OSes at the same time so you don't have to reboot constantly. Because of that, I do both
I dualboot Ubuntu, using Wubi
I run Debian, ChromeOS, Android and Ubuntu within virtualbox
If my dad gifts me with a 2TB HDD of christmas, the first thing I would do is install multiple OSes on it!
By the way, can I boot my Wubi disk within virtualbox, somehow, or the other way (boot virtualbox with wubi?)