Differences between the Flex and Force
My recommendations: Heart rate monitor. Integrate this as a "goal" feature. i.e. hitting your target heart rate for 20 or so minutes should be a goal integrated into a smart device with this many features. This would be a big improvement. The calorie count feature is iffy at best. I seriously doubt that i am expending 3800- 4400 cal per day this seems to tell me or I"d be dropping weight big time. 10,000 steps per day goal... That should be adjustable to at least 12 or 15 thousand steps per day.
A lot of new Smart Watches are integrating these same features into their devices. Fitbit needs up one-up them with some of the earlier mentioned features before they are left by the wayside.