I am also not a big fan of KK equipment, but I do have their gear drive 72" tiller. Have owned it about 5 years. I broke the rear tail gate hinge and rewelded it but that was my fault. I broke the chain on the tail gate a few times but again my fault. Now I attach the chain with a peice of wire. The wire breaks instead of the chain. Tines are about half worn down. I have used it in some ground that was so hard, I had to have tractor in 4WD or it would push the tractor and stall the engine from being too aggressive. I would buy another one if needed.
My only complaint is that the bottom hooks on my spee co quick hitch are too fat to fit between the pins and tiller. I just remove the quick hitch when I need to. Someday I will weld on an extension where the pins are located and bring the pins farther forward.
I still have the original gear oil in the drive. No leaks. (That reminds me to check it this spring - its been a couple of years)