I have a friend who has lost loads of weight with Weight Watchers (over 100 pounds!) and she has one - she likes hers.
I need to make a real effort to lose lots of weight, and I know very well that I need to move more as part of that ... but I'm a sad lover of gadgets, and anything that says 'Apple' on it, so I've got my eyes on an Apple Watch - I love the look of the acticity tracker on that as it's very visual - instant visual gratification from meeting your goal each day (I'm shallow like that!). I don't need it to monitor my sleep, so having to charge the Watch every night is no problem .... just need to save up for one now!