Retina Air running windows?

If the rumors are true, (and they always are) a retina display macbook air is releasing in Q3. This is the first mac I'm considering over a windows PC, and I'm fine to give OSX a try, but I need to know one thing:

Does windows run as well on macs as it does on normal windows laptops? Im pretty sure it does, as that's what many people say. I just wanted all of your opinions. I have a 2011 Vaio Z right now, and an Air would be a significant downgrade in processor speed and ports (HDMI, ethernet, VGA, biometrics) but thats ok. I'd probably end up keeping the Z in addition to the AIr.

Buy anyway - your experiences running windows on a mac?