I've been using one of these Snark clip on tuners for a couple of years now, and have to say the difference between this, and my old Korg tuner is night and day. Just to explain, this is only used at home, and on just on Electric guitar, and my acoustic, I don't use it in a live band environment.
I have the older version of the SN5 Guitar Bass and Violin, and can only assume the new version is better, though not sure how it can be, my one works flawlessly. It clips nicely on to the headstock of all my guitars very nicely, you can adjust the angle very easily thanks to the ball and socket between the display and the clamp, so seeing the display from any position is great. The display itself is really easy to see, and has brightly coloured sections to show if your sharp, or flat.
Very simple to operate, it has one large button on the front which you press to turn it on and press again to turn it off. I would highly recommend you turn it off once you've tuned your guitar to extend the battery life, even though it will go off automatically after a period of time.
Here's some places to check them out.ebay.co.uk