Husqvarna trimmers are the lightest out there at 9lbs. the 2 stroke versions. the 4 stroke Honda version is only a little heavier. 11lbs. about equal to the weight of a stihl trimmer but the husqvarnas are better balanced. at least to me they are. I've never picked up a stihl trimmer that felt "right".
I can mow all day and only use half a tank of gas in the trimmer.
that's another thing. the 4 strokes use less gas because you can trim at half throttle rather than full throttle like the 2 strokes. you also don't have to spend money on oil to mix with the fuel which saves you even more money.