I dropped my Withings stuff after constantly dealing with inconsistent syncing behavior. I got a body fat percentage weight scale and a blood pressure cuff from essentially no-name brands on Amazon, and both sync instantly every time. The blood pressure cuff doesn't even require me to have the app open on my phone.

Tough to beat compared to Withings' system, which seemed to rely on everything going to the cloud, then going back to your phone, THEN Apple Health, if you're lucky. With each of those steps being on whatever interval it decides.