I've been using Linux Mint as a VM for a few months now, ever since a few of you recommended it. I am really liking it! MUCH better than the latest Ubuntu versions, especially on speed and efficiency. Plus unlike Ubuntu, when I do Virtualbox updates, I no longer have to go through command line inputs to resize the screen resolution. It shows up correctly every time. I'm also using it on my travel laptop, mounting from USB for internet surfing on airport, coffee shop, etc connections. Super fast boot up time.
Anyway, recommended.
On a tangent, I'm now hating Win8 in Virtualbox. I tried doing the Win10 upgrade to it a while back, and for whatever reason, it's not supported in Virtualbox (also discussed here when I was having problems - apparently it works fine in VMWare). Anyway, ever since Win10 failed to install and it rolled back to Win8, it's been doggy and glitchy. I think I'm gonna kill the VM and reinstall with an extra copy of Win7 I have laying around.