If you would like to go with the Husqvarna 525LST, take a look at the Redmax equivalent: BCZ260TS. Specs are below:
RedMax Trimmers BCZ260TS
10.8 lbs, very well balanced and light weight as well. It has a different carberator than the 525LST which I think is much better than the 525LST. I bought this trimmer last spring and have also owned the 525LST in the past. The Redmax has been very reliable...starts easily, good power, and pretty good on fuel. The only drawback is that since it's a high torque model, it's geared lower so the head doesn't spin as fast as the non torque version. This works well in thick grass but for everyday trimming, it doesn't lend itself to quick clean cuts like a standard head does. This drawback is way more noticeable on the 525LST but not as much on the Redmax version.
I also purchased a Sthil FS94 last summer and it has been suprisingly really good so far. I had an early version back in 2015 but didn't like it as it seemed to have no power. This past summer, my dealer convinced me to try it again as he claimed Stihl had upgraded the carb. From my experience so far, it seems like he was right. This unit is lightweight, quick, strong in power, and quite good on fuel as well. I swapped out the standard auto cut head that it came with for a speed feed head. It's been great so far.
Echo/Shindaiwa are also excellent trimmers as well.