I had the 900 for a month or so. GREAT screen and a really nice looking phone. Ended up walking away from it (sold it on Ebay) as the app selection was horrid. Many of the apps I downloaded were poorly programmed and buggy. Facebook was pretty darn bad. Also, at the time, it only can in 16GB version which was a bit tight for me.
The 920 looks tempting but the lack of apps is a killer. Still, the UI was buttery smooth and, at the very least, right on par with iOS in my opinion.
Very attractive phone though. It looks tempting in pictures for sure...