I’m not sure if Lemmy, kbin, or something else will work out to be the community favorite, so I’m trying out both and would encourage others to do the same.
Normally, you can participate in a Lemmy community from kbin and the other way around, but kbin.social has been dealing with a DDoS attack or some such, and its mitigation measures are making that unreliable at the moment.
/m/flashlight should federate with Lemmy, but you’ll generally get the best UX when you’re using the same software.
There were federation problems with both kbin.social and lemmy.world during the initial massive influx of Reddit users. Both seem to have resolved the major issues.