To me, Android is just too fragmented. I appreciate how open it can be, especially if you root it. However, when I look at a phone, I want it to last long and remain efficient under the standard "2 year" contract.
I got my Android device when it first came out, and it was considered close to a premium phone. My dad got the Galaxy 1. Both phones are slow, buggy, and have stopped receiving any sort of updates, which makes me miss out on all the features IC and Jelly Bean provide.
Also, I am personally not an app user. I mean, I have about 40-50 apps and only use about 5 consistently, 10 overall. If I were to get an Android phone this coming holidays, it would be the LG Nexus, just so I can always receive Google updates.
I do enjoy the customization of Android, but on the flip side, it is a time consuming thing. Mainly because I am so OCD about these sort of things, and I spend hours until I get it "right".
I've played with Windows Phone several times, I've got a chance to handle the HTC 8X, and it's a really nice phone. It runs efficiently, works well, and is good for a "business" oriented person like me.
Overall though, I'm a lover of all tech. I don't enjoy submitting myself to an "ecosystem" despite some benefits it can give you. I run a MBP, might have a Windows phone, and will probably get the updated Nexus 7.
Also, the camera on the Lumia 920 is just flat out stupid (in a good way). If you do your research, it blows anything right now out of the water, and I really mean that. Having a camera phone like that would be soooo handy for me.
Here are two good examples of the Lumia 920's camera in action.
http://www.theverge.com/2012/9/7/3299784/nokia-lumia-920-pureview-camera-hi-res-photos
https://www.youtube.com/watch?v=ARckSCU8vMw