I've also been on the prowl for a good one as well. The FitBit family is a straight no-go, since they're more than happy to fade into irrelevancy with their own stuff than play nice on HealthKit. Misfit will integrate steps into HealthKit, but sleep isn't syncing. I'd ideally like something low cost ($100 or less is the true sweet spot) that will integrate into HealthKit now that we know the Apple Watch isn't meant to do sleep tracking.