I have a Tanita body composition scale...(glass surface, got it as a wedding gift, so don't know the exact model off-hand). As far as my experiences go...

It seems to be consistent with weight and BF% readings as well as body water, etc...
It's accuracy is debatable in my mind. My BF% numbers seem high, especially since I also own a hand-held analyzer. Both seem to be consistent in themselves, but are about 5-8% different, so that gives you the idea of what kind of range of acuracy you're dealing with. I've never had a professional analysis, but I'm geussing I fall between the 2 analyses.

The Tanita one works well as a scale, allows you to save your age, height, sex profile (a few of them)....it's a little heavy as a unit, probably about 8lbs or so, but I like it.

the hand-held analyzer is definately cheaper (~30) and is also easy to use. It does however give you another piece of equipment lying around. Oddly enough, they used the hand-held unit I have at the gym I go to when doing initial training program meetings...I thought they'd have something a little more scientific. Let me look to see if I can get you a link to this

Edit: here's a link to the hand-held one http://bigfitness.com/bofatan.html but either I have a scaled down model or they've been marked up significantly in the past couple years...still cheaper than a scale, but not as much

Yes what TriSooner said, go online and look for "sexy composition' monitors.

I am getting the Irongirl Innerscan Body Compostion Monitor for Christmas!It's supposed to
monitor your: weight,bodyfat%,bodywater%,musclemass,bonemass,daily caloricintake,visceral
fat&physique rating. At least i hope it does! :)

Thanks guy. That narrow my search. I will probably keep looking around.