I was a firm iPhone guy for years - all the way back to the very first one. Switched to WP8 and the 920 after having one too many disappointing customer service experiences with Apple (seriously, since Jobs died, the company seems to just not give a rat's ass about it's own customers anymore.)
All in all, happy. The 920 isn't the Jesus phone anymore than the iPhone was, or is. Lots of things great, some frustrating things as well. Off the cuff,
Things I Love:
-huge, gorgeous screen that puts the iPhone's to shame imho
-love the WP8 interface with tiles. Much more intuitive and like the instant access to data
-Bing maps >>> Apple maps
-Nokia Drive works fantastic, I use it frequently when in areas I don't know well
-Love the lock screen and how customizable it is. Blows Apple away here.
-Great low light camera
-Truly impressive video capability
-while I don't like the keyboard itself (see below), the autocorrect works really, really well
Things I don't:
-the app differential, as much as people hate to hear it mentioned, is real, unavoidable, and legit. Super frustrating seeing all these great apps (Stick-n-Find, Zite 2.0, Instagram, Pocket, etc etc etc the list goes on) available for iOS and Android but not WP8. Hopefully that will improve with time. Hopefully. I'll be thrilled if and when it does, but I won't be shocked if it doesn't.
-pathetic game selection compared to iOS
-no true Facebook app. The microsoft make-do version is terrible.
-no true notification center
-while it's easy to "get in the door" so to speak, I think there's somehwat of a steep learning curve with WP8. maybe it's just me and the fact that i had been using iOS exclusively since 2007
-don't like the way you switch between open apps
-don't like the keyboard. maybe it's my big hands, but the iPhone's was easier to type on for me
-extremely disappointing daytime camera results. I'm a photo nut, and all the people who say "it's GOOD, it's just not GREAT" are wrong - imho. I think the daytime camera function is mediocre. the iPhone 5 is *superb.* Could be how apple's camera renders things, and I'm very much looking forward to the Nokia update. Hope this gets fixed, and fast.