As always before making a big change, be sure to backup your Windows install before attempting this. It didn't work for me, in fact it wiped out my data partition. Perhaps it was a mistake on my part for installing it there, but I've kept data (including VM's) separate from my OS install for years.
Wubi for Ubuntu wasn't much better. I installed that on a laptop over 2 years ago (my first Linux experience), it was running fine. One morning, I couldn't boot into XP, although I could boot into Ubuntu, even though it was installed "inside" of XP. Weird.
Fortunately, I do backup on a regular basis, so the only thing that I lost was time.
"Making marijuana legal nationally would not only save valuable prison beds, but also pay down our national debt in a responsible manner"