Personally I haven't settled in on anything yet. I have accounts on several different KBin instances, a couple Lemmy instances, and Beehaw (which I guess is also a Lemmy instance)
Currently for me it's between Beehaw and Kbin. I like I can use either account to interact with either so at the end of the day it really doesn't matter. Kbin looks MUCH nicer on the phone, but I like Beehaw's moderation, broad-topic communities, etc. Alone, Beehaw would be too restrictive. Combined with Kbin and a couple Lemmy communities, eventually it's going to just be a matter of using your favorite username@whatever and deciding which front-end you prefer. Beehaw is a little better for people that want to avoid porn and stuff though.
If one platform begins developing much faster than the other, switch! Have a few accounts subscribed to all your favorite communities so they're all locked and loaded and ready to use.