not all.
the only real problem you should have is games. games or the myspace app.
here's the deal: bigger resolution means things that are res-specific wont fit the screen.
it's pretty hard to play some puzzle rpg like game that's the size of a quarter, right?
from my experience, everything else carries over perfectly or better. just make sure you get a hold of any prerequisites you might need.
for example. TellMe: you need to install MSVC (MicroSoft Voice Command) first. it came preinstalled on the i910, but not i920. why? who knows.
other then that, go nuts!
