I too have had MY say.
This is NOT a new topic for I.
The thing I found most interesting was that a hip-mounted clip will be more accurate at counting steps than a wrist-worn device. AMEN to that. I now know that, even with a $1,750 top-end Garmin MARQ Expedition, at least 10% of the steps I register a day (and I average over 10K/day) are FAKE. I just use the step count as a guide — try to do 10K+ as a goal. If I am going for a proper walk I use GPS on the hope that it is more accurate — but GPS has issues too, i.e., trees/tall building, going back on yourself (like walking around in tight circles).
It talks about heart rate and calorie burn too. I am pretty happy with my HR tracking since I have checked it, so many times, on multiple devices.
Anywho, skim through the article. You are sure to find a few things that will interest you.