Here I am, posting from my 920. Overall, its very good, but it has its quirks. It's seriously super fast and smooth, very integrated, and is a good experience. My biggest complaint is that there doesn't seem to be any good synching options for my Music Pass collection. Tips are appreciated...
Nokia Drive is pretty good, but it only says the street name once. I would rather have it repeat, like any other GPS. BUT its the most fluid and quick navigation device I've ever used!
Talk-to-text is very good. I just wish it was offered in more places, like this text box I'm typing into right now.
The predictive text is the best I've ever seen, although it does miss some pretty obvious things like capitalizing the first letter of the first sentence of a new paragraph. Only sometimes, though. Odd.
OneNote on the phone is surprisingly good.
Email support is stellar; I have 3 Exchange accounts set up and I can keep them beautifully separated, just how I like them. But you can combine them, if that's what you want.
The mobile internet explorer is quick and smooth, just like the rest of the phone.
If I had to complain, the list is short. First of all, the lack of a hardware silencing switch is a step backward. Also, the sound scheme is all over the place volume wise. For example, the dial tones are louder in volume than the ringer - WTF? And while I love the seamless Facebook integration, it's just a hair too limited, so you'll still need the Facebook app anyway. Finally, when texting, the send button is not on the right side, which feels awkward.
I much prefer this phone over the Galaxy S3, which I came very close to buying. I'm glad I waited.