QUOTE(LesterLou @ Nov 5 2009, 09:37 AM)

I have one and like it as well. However, it's not instantaneously accurate like you would wish it to be. The instructions say that it is most accurate when the readings are taken in the afternoon, after you are fully rehydrated. It also says that you should take an average over a month rather than paying attention to any one number. The fat percentage is calculated as the inverse of the water percentage, so if you're dehydrated, you'll appear to be more fat. It tells you the % of fat and % of water... NOT the % muscle mass, which is truly the interesting one.
I do know that when I am dehydrated after a massage or particularly challenging workouts, the hydration number is lower. And I have seen a reduction in my fat % over time.
If you are the type to freak out over any given reading, don't bother. You'll drive yourself crazy watching the numbers spin for no apparent reason. They are even more difficult to control than your weight. On the other hand, if you can watch the numbers with mild interest to get a general feeling about your general progress, then great. I have been happy with my purchase and I've had it for a couple years now.
Thanks for your input. I bought one and we'll see.