My JD dealer gave me a roll of the square line with a new timmer last year. Winds out nice, easier to load and does a better job of cutting thru sod and roots.
i'm still sold.....i used the trimmer again, for the first time this season.......trimmed right up against the landscape rocks.....NEVER bumped the knob.....
Another vote for the Gatorline. I run the magnum gatorline on bth a Husky 252Rx spacing saw and on a little Honda trimmer. Its the best line ive ever used. Lasts along time, even in the spacing saw. A little more money , but its worth it.