I don't have a direct comparison with the Apple Watch, but I realise that the ScanWatch values are accurate. I also wouldn't be sure whether the Apple Watch is actually the reference.

I already have the umpteenth version (I've been using it for years and am very satisfied) and think it's very good! I can't say whether an Apple Watch shows better results, but the Withings series is a very good guide in terms of weight and sport... I'm also very happy with it and can therefore only recommend it! 👍🏻

Apple Watch is no comparison, you would have to go to the hospital to get accurate readings for comparison
Mine is completely sufficient and it works perfectly for 20-30 days without charging, which the other watches cannot do