I've owned a KKII 72" tiller for 4 years. This year, I not only did my garden, but I also tilled several areas of native soil where I wanted to take 6" of topsoil off with my FEL. Even though I hit several football-sized rocks, the tiller did fine with no signs of any damage. If the Countyline stuff is KK rebadged, then I think you will have no problem with it.
Whatever tiller you buy, be sure the gearboxes are filled with the recommended oil, the tiller is greased, and the slip clutch adjusted before first use. These things are not done by the dealers. The gearboxes are shipped dry.
After first use, go around the tiller and check fasteners. All of them are subject to a lot of vibration and bolts loosening with use. My gearbox cover needed tightening on my KKII. I notice a small seep and took care of it before it got to be a problem.