I got a BodyBugg in November, when they were on sale for Black Friday. I got the SP model, which downloads to my iPhone so I can track my burn and log my food from anywhere. Now, when I first got it, I was so excited, and began wearing and logging food every day. I checked my calorie burn multiple times a day, and when I wasn't reaching my desired 500 calorie deficit daily, I would do extra activity. I lost 6 lbs. in 4 weeks - I was REALLY excited. For me, this was what I had been looking for...I know it's not 100% accurate, but it's close enough that it gives me a good picture of where I am at any point in the day, and if I need to make myself move my lazy butt that night instead of watching TV, seeing the numbers helps.
Now, Christmas came along. And I decided I would forgive myself. I ate less than usual at parties (and home!) but still ate my favorite treats. But then I had trouble logging them, because who knows how many cals are in grandma's pie that my friend made and I can't get her to give me the recipe because it's a family secret, so I stopped logging. And as of today, I haven't started back.
And along with the not food logging, I'm not checking my burn every day...or even every other day! Oh, I'm still wearing the bugg, I actually feel kinda weird without it, but for this to work, I have to be disciplined enough to log food, check burn, and then do something (i.e. move my lazy/exhausted self at the end of the day if I'm not where I want to be). So, it's a tool, just like lots of other tools. I know that it gives me the feedback that I, personally, need, if I choose to use it.
So, yesterday, I started food logging again. Because DH and I just signed up for the Princess 5K at Disney and I have 3 weeks to get into enough shape to walk/jog 3.1 miles in one go. (I'm a naturally fast walker, about a 17 minute mile, so just need to get slighter faster in 3 weeks and we'll be fine with the 16 min/mile pace.)
Anyway, if you're looking for some fitness tool to give you feedback, then I'd recommend the BodyBugg. But if not, keep looking, I'm sure there's something out there to meet your needs!