I decided to return my 920 in favor of the 635 (with a reminder what I also have a 520).
I knew that a WP device wasn't going to be my faily driver, and as a backup device I just didn't think the 920 was the right fit for me. Don't get me wrong, it's a very good phone. Super solidly built, fast despite its age, and a worthy entry device for a more full-featured WP experience. However, despite it's being a tank I found it to just be too heavy for me to carry around in additional to my HTC One daily driver. The camera wasn't very good, imo. From the stills I've seen it was really, really incredible with Portico, but most pictures came out with too much noise for my liking. I didn't see much an improvement over the One in regard to picture quality. Also, as I planned on using a backup WP as a media device, the 32 gigs of built-in storage, while very nice, ,wasn't enough for the few apps I use and all the music I carry. In this regard the 635 was better for me, especially with the recent update to Xbox Music that makes externally-stored media usable.
I liked the 920, and for $140 dollars it was sweet. Just wasn't the right fit for me. If it were lighter, had a smaller footprint, and an SD slot I would have kept it without question. 635 has a leg up for me because of these things (and better battery life, too).
If you got a 920 in this sale, it's definitely worth it. I also recommend the 635. I like Windows Phone a lot. I know there's a decisive idea of the potential of android apps running on WP in favor of native apps, but if Windows Phone closed the second tier app gap for me then I'd be using this daily. I know everyone says that, though.
Good luck to all who have new 920s!