I don't use Fedilab so can't say. Looking around Fedilab the biggest difference I can see is that this will work on platforms other than Android. Because I'm writing it in Flutter it will run on iOS, Android, Linux, macOS, and Windows. I spend most of my time dogfooding on macOS when I'm working on the road and Linux when I'm working from home. This is specifically targeting Friendica so it uses various API endpoints that it supports. Sometimes the Friendica specific ones work better. Sometimes the Mastodon ones work better. Sometimes things need to be tweaked as I start using it so we can do things like paging long lists of contacts, etc. The thing Fedilab has going for it is that it has been around for a year or so. They therefore are way ahead on stability, real world usage, etc.