Mirror's Edge is a game I would recommend anybody looking for something different should try. On your first try it can last about 5 to 6 hours, but once you get better you find more paths through levels, and can bring that down to 1 1/2 to 2 hours. This is one of the main joys of the game, is the replayability as you explore to find quicker ways through the levels. The story is not very strong, but it is easily ignored and only really needs to give a vague setting as to why you are in a certain area. The running feels very solid and responsive, and the game runs very smoothly.
The only real issue I have with the game is that there are a few parts in which you need to partake in the difficult combat system. Most are avoidable, but there are some forced fights which can get rather tedious, as this is a game where you are supposed to run and flow smoothly from wall to wall, floor to floor, so stopping in order to fight takes away from the real strong point of the game.
All in all, if you want something different, then I highly recommend Mirror's Edge, if you enjoy platforming, especially in the first person perspective, and for £10, its worth every penny.