re: Do you guys use an edger or just edge with your weedeater?

Something else not mentioned is the quality of the driveway/sidewalks. I've edged a few houses, with an edger, where the sloppy concrete pour would kick out the edger and ding the blade in the process.

To me! (For what that’s worth)! I think the edger cuts a cleaner line along the concrete.

I had an edger (McClane) for years, and it was significantly better, especially on concrete. That being said, I hardly used it, just to easy to keep using the weedeater. Also, not much difference along flowerbeds.
It was best if you wanted a narrow deep groove (like to bury a wire for a fido shock, or shock colar for a dog.)

I finally gave it away because I almost never used it.

Gas weedeater only. Use to have an edger, but they became impractical once weedeaters came into the mix.