KGT27B kawi if you can still find them. New model Kawi have upgraded the emissions to make the EPA happy but the loss of power doesnt make me happy. but this is true for all 2011 trimmers Ive been told. I run a few with the hollow steel shaft and I have one with the flex shaft. The hollow steel has a much better feel imo. The flex shaft have that slight torque delay that makes the trimer yaw a bit when you gun it. But overall power to weight I love. And at around $320 give or take a little I think the price is pretty good. Only other brand/model I can base my opinion on is that I ran "high torque" echo trimmers for years before making the switch over to Kawi and I am happy Im running Kawi now.
2008 F-350 Super Duty Dually gas guzzler
2006 Ram 3500 Dually Cummins Diesel
14x7 landscaping trailer
12x6 P&T hydro dump trailer w/leaf box
We run Gravely ZTRs and Prostance, Honda 21"s, Redmax Backpacks and Trimmers, Stihl Trimmers, LittleWonder loader, Kawi trimmers at the end of their lives and a bunch of stuff you probably have too