I have been using the bioforce HRV for about a month now and I have mixed results and feelings.
First off, especially since the last update it has been costing a lot of my time to get a proper reading. Even after resetting my device and all the other options. It shouldn't be the battery because the polar app indicated the battery was still full.
It might also be because of a few anomalities in the app:
1. As soon as the timer starts the connection indicator turns red for 2 or 3 seconds.
2. Also as soon as the timer starts there is either a drop or a rise in HR sometimes up to 20 from my actual HR. Then it slowly returns to normal(5 to 6 seconds).
This morning I also noticed something weird. Yesterday I could not do a reading. So I tried again this morning, my HRV was 95. But the weekly change indicates a difference of 1 while my HRV hasn't come anywhere close the previous month(see included screenshot).....