Had mine for a couple of weeks now. Size wise its not bad at all. I dont have the biggest hands in the world being female, but its nice to hold and not too weighty when the slide is up. Keys are a good size and easy to access, slightly "clicky" but that could just be mine. One thing which is very annoying is Sony have changed the use of the hash and star key, star on most SE changes to capital letters whereas on this one its sybols, a silly thing but when you are used to how a manufactuer layout a phone the changes are a pain and pointless.
Menu system is proper die hard SE, same as they have been since the dawn of time. (well, a while anyway...)
Screen quality is good and clear - One thing I find a letdown is the camera, having major issues with either everything being white and overlit with the flash or too dark to see, and blurry photos. Am still trying every setting on the phone so will let you know!
Runs very smoothly, the touch media screen has locked up once on me but I do hammer the phone and its on 24/7 so to be expected. Excellent sound quality for the music player.
Would advise getting a sceen protector to keep the touch screen working to its full potential.
On the whole, very pleased with it, with a minor let down on the camera.
Any questions, post here and I'll do my best to help