Only technical problem I've had is with the game using PC controls when I have the option to use a controller turned on, though this is more likely due to the MotionJoy drivers for my PS3 controller.
Overall I like the UI, though I do wish we could sort items by something other than alphabetical, such as weight or armor value. I love the favorites system though.
The other complaint I have is with the difficulty, I seem to die allot. I'm playing an Orc who wears heavy armor (all steel except for the helm, which is the awesome guard captain helm you get before your hands are even free), I also have the perks for heavy armor bonus and additional bonus if wearing all heavy armor. As a personal rule I refuse to play on the lowest difficulty in any game, though I think I had to turn it down from the 3rd lowest to 2nd lowest, and I'm still dying. I really like the combat system, guarding and countering is fun and adds strategy over mashing the attack button, but enemies seem to be able to randomly take off half my health bar.