FitBit Zip

I have one and I love it! It's super easy to wear (small enough to attach to bra or pants) and it gives me a more realistic sense of my activity level. It's especially helpful on those slow days, as it will take calories away from your daily allotment on myfitnesspal (of course, some people get upset by this and delete the adjustment when it's not convenient for them!). Personally, I would rather know what I'm burning so I wear it as much as I can and eat accordingly.

I highly recommend it. I had the ultra for a while, but didn't use the sleep tracker nearly as much as I thought I would. Given the price difference, I say the zip is worth trying out first!