I did… and it was a good experience.
The possitive: Windows is a lot quicker to navigate, and just check messages, etc, without having to drill down into the apps. The WP experience is a great alternative to iOS, and it doesn’t really take a lot (or steal) from it… it’s a fresh alternative. I personally love the Lumia 800 I choose, it’s a little more organic and feels good in my hand, not such an industrial coldly precise ID as the iPhone (my opinion). Nokia has some nice useful apps, not at all like the bloatware skins like carriers and manufacturers put on Android. And it has some nice integration with Windows 8, like contacts, SMS, etc. Skydrive and MS Office are also really handy
the negative: Whenever you hear of a cool new app, it’s usually only on iOS or Android… they come to WP last it seems and some never do. Some parts of the OS don’t make sense (but you could say that for all of them)… two examples are not being able to do screen grabs and not being able to take a business address you found on in maps to adding it as a contact. NFC doesn’t seem to be well integrated yet, some of the coolest stuff isn’t available. You still don’t have drag&drop access to music and files - you have to use Zune, which is nicer than itunes, but still a pain. The Keyboard is more tightly spaced than iOS too
I think you’d like it after a short adjustment period - took me about 2 weeks