I personally think that from a technical perspective OSX is the superior OS when compared against Windows. Linux could be better, but it's just not polished enough for my taste.
With that said, I've been using Windows as an everyday desktop for way too long to switch to OSX without feeling major pain (see: “how the fuck do I do <insert trivial operation here>”). I'm likely to stick with Windows just because I don't like change.
With that said, the MBP is a really nice laptop – a quality product from the box it ships in to the screws it uses. And the ones with the “Retina” display just have, by far, the best computer screen I've seen. I wish Apple releases standalone retina displays. You can bet I'm standing in line for those babies... I spent way too much time in from or the computer to not get the best quality displays money can buy.