Hmm... I have a Sony Ericsson K750i as well, but since I'm in North America, it has horrid signal reception (problem with all non-NA SonyEricsson phones in my experience). Its a more stylish and eye-candyish phone than my CX-75, but it wasnt fun not getting signal. So I've packed it up and am selling it to a friend in Dhaka.
Compared to the K750i, My CX-75 is lacking in a flash, and has a 1.3MP camera as opposed to a 2MP thing. Otherwise it serves me great and I aint complaining. Will target a W850i/W900i or a W950i next summer.