I did a lot of research into this at the start of the year.
The general consensus for all of these scales seems to be:
The ones you just stand on aren’t that accurate for body composition as the current goes up one leg and down the other and misses the rest of your body. So if you have chunky or skinny legs in relation to the rest of you, it’s going to over/under report your muscle/fat.
The ones with a handle thing are more accurate but considerably more expensive, and even then, they aren’t that accurate.
As such, if you want an accurate body composition readout, you really need to get a DEXA scan.
With that being said, as long as you understand the limitations of consumer smart scales, using one and looking at trends can still be useful. It doesn’t matter if it’s not 100% accurate as long as it’s consistently inaccurate, if that makes sense.
Because of this, there’s not a lot of point spending lots of money on a Withings or Garmin scale. For me it was a toss-up between the RENPHO and Eufy. I have other Eufy products, so that seemed to make sense, but the RENPHO was cheaper and I figured it was worth a punt.
I’ve been really pleased with it. The app is easy to use, syncs with Apple Health, and certainly for weight tracking, BMI, etc, it’s great. I just take the body composition with a pinch of salt and look at the long-term trends.
Hope that helps but shout if you have any questions about your new scale.