I just switched from a Whoop to the Fitbit Air. Whoop wanted $350 for a subscription fee which I just found really ridiculous. It's only been a few days, but the Fitbit Air might even be better at tracking sleep. And it looks like it can periodically, automatically check for Afib unlike the Whoop (?). The rest looks a little worse. But worth it to avoid a subscription fee. Not sure how Whoop stays in business TBH.