Get the RedMax LRTZ2460, it has the powerful strato-charged 2-stroke engine. We bought one about a year ago and it's been great. We've trimmed bushes with it every week since March, the blades are great- in my mind much more agressive than the Stihl counterpart trimmer.
One of my guys loves it, he said it cuts better than the Stihl because the blades are wider apart and tougher.
We ride Hustlers and stand on Exmarks.
Stihl and Redmax Handhelds