Charge 5, started using early October.
In general, I like it, and some things have gotten better since the first frustrating week, but there are still issues:
1) battery indicator on iphone app no longer registers correctly. Tiny greyed-out battery percentage indicator on the Charge is more accurate but is nearly invisible without a magnifying glass.
2) device can't maintain bluetooth connection to iPhone app. This makes syncing difficult and time-consuming. Even after turning on/off bluetooth and restarting device.
3) integration with Strava for exercise (biking) is confusing and weak. Sometimes, when using "phone" setting for GPS, recording works great; other times it drops out (even over the same route where it worked the day before). So I have to activate Strava as a back-up, sometimes ending up with "duplicate" activities if Fitbit works. Just delete the Strava activity if the Fitbit one works, you say? They're not really duplicates though: Strava data is much more accurate than Fitbit, but Fitbit provides the heart rate, which is why I bought it. So I lose something if I delete either one. But if I keep both, it shows inaccurate record of my exercise activity. Grrr.
