My phone has zero lag, an awesome screen, was speedy as hell when I took it to NYC recently, looks beautiful, and has ICS which is hands down Google's best to date.
With that said, and I'm not going to beat a dead horse, my particular phone has several issues which definitely ruin the experience for me. I have always told myself there's no way I'd get a Windows Phone 7- outdated hardware, limited OS, poor selection of apps, and a bad taste in my mouth from Windows Mobile 6.5, and then I played with the Nokia Lumia my brother just bought. That is one smooth, I mean buttery smooth, experience. Even with a single core, it puts most Android phones to shame as far as UI experience goes. They have limited apps, but the apps they do have seem much more...I don't know how to put, usable? I like their menu system, I like the tiles, overall a phone I thought I'd hate gained a lot of respect. They aren't quite there yet, but they are pretty close. This wasn't even a flagship phone, either.
I think when Windows 8 and the matching Windows Phone 8 (or 7 update, not sure how they're doing it) comes out, they will be a force to be reckoned with, with a seamless Desktop to mobile OS to tablet experience. So while I love my Nexus and none of the other choices would even tempt me a bit (except the updated Nexus, of course), I have to admit I'd be tempted by a top of the line Windows Phone with LTE, build quality of Nokia, and the (judging by reviews) fantastic camera they put in their top of the line phones. Bring on the flames I guess haha.
The only way anyone would flame you is if they never spent time with a WP7 phone. Back in 2010...it was the most fluid, buttery smooth UI experience between it, the iPhone and Android. As long as Microsoft doesnt make it worse...it is a sleeper hit waiting to get noticed.
