I had one for Xmas, it was in the drawer by March.
You need to be honest with yourself what you want it for, they do seem to do a decent job of knowing when your cycling – and you can start and stop activities and tell it after the fact what you were doing.
But.
Here’s the rub.
If you want to track time, distance, speed then Strava is better.
If you want to track calories used to lose or maintain weight, they’re useless, hopelessly over-generous.
If you want to track calories and track food intake for either of the above, the app is okay to crap, MyFitnessPal is much, much better.
If you want track max heart rate or average heart rate during running or riding, they’re okay, ish – they’ve recently got into trouble because their HR devices can be pretty inaccurate.
If you want to track your resting heart rate, they’re very good as this, but you really need to wear it when you sleep, not so great.
If you want a slightly cheesy looking digital watch that needs to be charged every 3-4 days, well they’ve got that well covered.
If you want to ‘subtly’ tell everyone how super fit and active you are by wearing one… well each to their own.
If you’ve got say an iphone, it can do all of the useful things that a fitbit bit can do, the HR stuff is either inacurate or really, not very useful unless you have the knowledge to use it – my resting heart rate went from 58 to 52 over the course of 3 months, great – is that information as use to me, not really and it’s a bit of a odd internet brag.