Back in the day the cat’s ass for heavy work that didn’t really require a big clearing saw was a Stihl FS 250. Spooled up really fast, 40 cc, lots of power. Really too much for the Stihl guard, it kept the line too short. Shindaiwa was another thing, but the dealer network wasn’t as good and I never saw as many. The lawn guys ran Echo’s smaller trimmers and they work great for them. Stihl’s FS 85 was the go to for lawn guys who ran Stihl. Mind, the Stihl stuff cost a lot more than the competition.
The FS 250 is NLA, and the FS 130 became the go to for that type of work. It was less zippy but still worked awesome. I haven’t bought a new one in a long time, but I think it’s been superseded by an FS 131. It’s probably a good machine. A lot of people worry about 4 Mix engines, but it seems like the landscape guys and farmers get great life out of them. I haven’t done anything with a trimmer other than the house in a long time.