The reciprocating blades are FAST. The only problem is, that they DO take some maintenance. You have to watch where you're putting them. then again, you still have to be careful with circular blades, too. The reciprocating blades are just like the hedgetrimming blades, except the bar is shorter, and they are a little more heavy duty. Personally, I like the idea of just using an angling hedgetrimmer head. These things rip through weeds and small brush at a width of the length of the bar and you only have to run the engine at about 1/8 throttle. If you have REAL thick grass - like in a ditch or something, this is where these things really shine.
Thank you, Dad - for always being the dad that you were. You truly are my hero. You always were.