I love mine.
Ive got the Flex and you can track food, water, sleep, exercise, steps and weight.
I don't usually track food but I always use it to track my water intake, and of course sleep and steps.
I was reluctant to spend so much on it, and although I got mine on offer with Amazon, I'd still say it was worth the money.
Personally the flex is enough for me, I'm not doing any sort of intensive training or anything, so I don't need more than this one