received mine today from cpw on o2, seems to be unbranded which is good. I'll reserve passing judgement for a couple of days but i'll give my inital thoughts:
slide could do with sliding down just a little bit further to make the 1,2 and 3 keys a bit easier to get at (may just be i've got big hands)
i prefer the SE method of having space as the # key on the bottom right as opposed to the 0 key
miss the jog wheel of my p910i for searching through the predictive text suggestions and scrolling
not having the cancel button on the keypad is a bit of a pain for texting one handed as its a bit of a stretch.
a seperate button for the centre of the dpad would be good
much easier to get it hooked up to the pc using the pc suite compared to my experiences with SE software
too many keys on the bit underneath the screen. I'd rather have just the two shoulder buttons, the answer and end call buttons, and the d pad. Move the 'pencil' and cancel onto the keypad(as they seem mainly for texting and dialling), and move the menu and multimedia onto the side, or drop the menu button and make it the right shoulder(on the default screen view) rather than the gallery option, which i see as a gimmick than actually useful.
speed seems good so far, not spectacular but similar to my p910i, the test will come when its has hundreds of messages/emails etc and whether it slows down.
i'll see how it goes over the next few days, before i decide whether to keep it or return it.