I bought a STIHL FS38 last year. Smallest they make I think. Uses 080 line. Miles ahead of any of the box store brands. The only attachment Is a poly blades I think.
My wife uses a craftsman electric trimmer her dad gave her. I like it for a couple of things I do around our store. It has a head that's not auto feed. It has a groove all the way around with 2 notches. The head holds a few feet of .250 or so line. You pull a some out about half a wind and switch notches if that make sense. I have only had to do it once this year so the thick line last a while. I wish I could get a head like that for the Stihl.
I bought a Bowens (iI think) gas trimmer with ran great last year but I forgot and left gas in it over the winter from October or November. Ran when II first ran it this year but now it won't run. I think the primer or lines are gooped up. It runs on a squirt of starting fluid so its fuel related