I started out with this one, and for a basic scale it was just fine. (You really do have to place it on a flat, hard surface to get accurate readings, though.)
Then I decided to get a bit fancier -- doing a lot of quantifying myself -- and I got this one. It's been a solid performer so far, and the app is nice and simple enough to use.
I'd also recommend getting yourself a good tape measure -- this kind makes it easier to measure yourself -- to track changes that might be happening even when the scale isn't moving.
I'm not sure of your price range, but I'm enjoying the Eufy (regularly $40) I bought off of Amazon (but I think it was $5 off when I got mine): https://www.amazon.com/eufy-BodySense-Bluetooth-Composition-Analysis/dp/B01MFAABKO/ref=asc_df_B01MFAABKO/?tag=hyprod-20&linkCode=df0&hvadid=198069016725&hvpos=1o1&hvnetw=g&hvrand=17060280447588322974&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1017518&hvtargid=pla-379631475963&th=1