I've got some of the Kumho KW23's. Just put them back on again for the third winter. They've covered just under 10,000 miles over the last 2 winters and have about 5mm of tread left on them. They had 9mm to start with, so hopefully they'll get me through this winter before they're no good.
They're a little noisier than the summer tyres but apart from that it's hard to tell the difference, except that I can actually get out of my back lane and up the bank in the snow
They also appear to be about £10 per tyre cheaper now than what they were when I got mine