Fitbit. I was just about to pull the trigger on the Apple Watch Series 6 when I checked a couple of articles that noted the battery issue, which is a real thing for me. I'd pay the watch cost without hesitation if the battery life was comparable. I can go 4-5 days without charging my Fitbit - if I had to plug it in at night to charge, I'd lose the sleep tracking (and I'm just not disciplined enough with my devices to charge it earlier in the day). I don't mind most of the other suboptimal performance things about the Fitbit other than the music and podcast playback. And the battery upside of the Fitbit outweighs the downside of the Fitbit's crappy media playback.
Even if the price were the same (and I didn't already have the Fitbit) I might get the Fitbit . . . I suppose that tells me what I value most.