Sony are releasing the PS Vita slim to the UK on February 7th at RRP of £180 - link. The slim is 20% thinner, 15% lighter and has a LCD rather than OLED screen - this cuts down costs, but on the positive side, increases the battery life by over an hour. It also does away with the 3G option.
Considering the cheaper screen + the presumably more efficient manufacturing process, £180 is bizarrely (and rather disappointingly) more expensive than you can get the current PS Vita in the UK (Amazon are selling a few packages between the £160 to £200 mark depending on the bundled game).
I'm now wondering whether to pick up one of the last few with the OLED screen and 3G, or wait till the price drops on the new version to make it more tempting. From most of what I've read, the LCD screen offers a less striking experience, but with more natural colours and obviously longer battery life has got to be a good thing. The weight, and layout of the back touch screen and a couple of the buttons also makes it an easier beast to handle.