Peter Gamma from www.petergamma.org has strongly criticized Rob ter Horst, especially his scientific justification to choose the Polar H10 as his reference device instead of research and medical grade ECG devices. Whe have reviewed this topi here:

090. Review of Accuracy Studies of Consumer Grade Heart Rate Monitors: Methods, Testing Protocols, Reference Devices

But Rob basically did not react on critizism, or only in a superficial way. For instance choosing 2 or 3 subjects instead of only one. But this is still not statistically relevant. As you can see in the following video, post-doctoral scientist Rob ter Horst continues to sell smartwatches to simple people has highly accurate, wich they are not:

Rob ter Horst: Best Sports, Sleep & Health Tech: Black Friday Tips!

There are hardly any scientific studies published in scientific papers about Rob ter Horts more than 100 smartwatches. And from what we learned about those we came to the hypothesis that these smartwatches deliver data which are difficult to be reproduced.

Peter has given up hope as far as Rob is concerned to contribute to this discussion, although he would be highly qualified to do so. And the only solution for him personally is to stop watching his YouTube channel.