Gadgetbridge looks better in terms of privacy, but for some reason I'd chosen Notify and Fitness for my mi band 4 and some xiaomi body scales. Probably because it had more features than gadgetbridge.
I will definitely try Gadgedbrige again when there are less active covid cases in my city so I can continue working out outside.
My main sport activites are free weight lifting and longboarding (long distance, 10+ km, no trick like on skateboard).
In my current app I really like trend charts, especially weight trend (and recommendations on how to lose more weight based on my activity). Do not remember if they were present in Gadgetbridge when I last checked. But I don't like that the app I use now is slow on my old android (looks like unoptimized react native app).