Good sliders are often petite. It is an obvious benefit of the format that because the number pad is hidden the phone can be made that little bit smaller. But not this one. It measures 99mm tall when closed, growing to about 130mm when opened. It is 47mm wide and 14mm thick. Weight-wise you are looking at 94g.
I have some issues in terms of the general ergonomics of use. Sony Ericsson has failed to provide anything much to get a grip of as you slide the two halves of the phone apart. I found pushing at the bottom of the handset to open the slide and pulling at the screen to close it were the best options, but a good grippy ridge somewhere would have been easier to use and helped prevent greasy finger marks spoiling the screen.
With the slide opened the number pad is large, but there is a big lip along the bottom edge that could hinder fast access to the bottom row of keys - megatexters take particular note.
Finally in the gripes department, I loathe the front mounted navigation key. Sony has a bit of a reputation with me for coming up with some difficult buttons and this one is right up there with the worst of them. The round navi button is surrounded by a raised frame which might look rather nice, but also makes it more difficult than it should be to hit the button for left, right, up and down. C'mon Sony Ericsson, the button should be raised, not the surrounding frame.
One area where this phone excels is its screen. A 262 thousand colour 240 x 320 pixel job which measures, according to my ruler, 32mm wide, 42mm tall and 2 inches diagonally. It's also sharp and vibrant.
With features like Web browsing, RSS reading and mobile email a good screen is vital, and so it is great to see one here. And there are other neat touches. I really like the tiny vibration you get when settings and selection keys are pressed, for example.