This is a thing of beauty. A pure circle of toughened glass on which to stand. A great big clear digital display that you can easily read while standing on the scale. It will weigh up to 25 stone, and you can adjust the display to read either in kilogrammes, to the nearest ).050 kg, or in pounds, or in stones and pounds, the latter two both reading to 0.1 lb. There's an adjustment switch underneath for this - a bit fiddly to find. (As a cup of tea weighs half a pound, then you can see that that's pretty sensitive.)
We've had ours for a couple of years, so it's too early to see how long the batteries last, but I would guess that they will be like watch batteries and be good for many years.
Operation is easy, and saves battery energy. You simply jar the scales a little and they reset to zero. Stand on them and they read immediately. The reading changes a little as you stand, especially if you move around, but once it has been stable for about a second it then flashes before giving a fixed reading for a few seconds more. It then turns itself off.
You can get these for about £60 from Amazon - retail is just under £100. For a good, reliable and handsome piece of kit, this does the job.
Batteries are CR2032, which are about the size of a penny coin. It takes two, and you can typically get two for about £3 including postage at Ebay. I've also seen ten of these for a fiver, but it's probably not worth having that many. They are pretty easy to fit.
UPDATE May 2009
I've used this at least twice a day since buying it, and there's no sign of batteries giving out. It's very easy to clean and has remained in perfect condition.