Sony Ericsson was showing off their Xperia X10 and the X10 mini. The UI was fluid on the X10 and the mini seemed to have more of a redesign to fit the smaller screen. Icons were in the 4 corners of the main screen on the mini as opposed to the typical Android arrangement. Both phones were responsive to touch and input. Sometimes you felt like you were lost in the 'blueness' of the UI's but overall it was a good experience. No multitouch from hands on experience. Maybe this will change however at some point in the future.
Sony Ericsson Booth At CTIA 2010
Xperia X10 At CTIA 2010