I've got a 13" MBP, and on the hardware side NOTHING in the windows realm comes close to the MacBook. The touchpad is an absolute joy to use, I can not stress that enough. I'd buy the MBP again just for the touchpad. Another positive thing is the screen: I have yet to see a Windows laptop that has a screen as good as the MBP (I also own a Vaio, which are well known for their screens). The hardware also has some negative stuff: the aluminum construction means that it gets really cold when it's cold around you, and worst, it gets really, really hot, so much that sometimes I can't use it on my lap... Another issue is the palm rest: the edges are really sharp and dig into your palm, making it uncomftable use for long periods.
On the software front I prefer Windows:
- I'm more productive using windows;
- I prefer Windows' design to OSX's excessive animations and skeuomorphism,
- I'm an office user and office for mac is **** on earth,
- I like the windows 8 metro interface for when I want to chill out and have fun on my PC, and use the desktop when I have to do some work,
- Sadly I haven't had much success with Windows 8 running in bootcamp so I'm stuck with OSX when I'm on the go :/ (my Vaio is a desktop replacement that I use when I'm at home).
Hope this helps you