My 5' King Kutter has served me well for three years, and its previous owner for an undetermined number of years before that. It's not the highest quality implement you will find, but buying used for $200 you don't ask for much. I've had no trouble with it except for the pivot for the tailwheel seizing and needing regreased frequently to keep from tearing things up when I turn.
My NH 1920 has no problem running it, even when bush hogging pasture for the neighbors with grass well over the hood. It can be bogged down in very wet, heavy grass as I mow through wet spots, but so would anything else; you just downshift or reduce your width of cut.
It's a cheap implement, but appropriate for the amount of work I need from it. I would certainly upgrade to Woods, LandPride, or Bush Hog if I was making money off it or cutting more land.
I use the lift, block, and angle grinder method of sharpening, with good results so far. Your mileage may vary...