I ran a Yazoo/Kees ZT max 52" and 23hp Kohler almost all of last season. They are good solid machines, but I never was quite satisfied with the cut quality, had to do double mowings quite a bit. After the dealer and I had a big disagreement I traded it for an 04' grasshopper mid mount and I could tell a big difference in cut quality and speed. Overall they are a solid mower, I put 300hrs on the one I ran, had no mechanical problems, just didn't cut as good as I thought it should.
I have demoed one and was impressed with it! There are a lot of these mowers showing up around here and everyone is very pleased with the cut and performance so far. I have only heard of one complaint which is if you buy one buy it with the suspension seat!
This is my second season with a 61" Yazoo Kees ZTR. Purchased used with 150 hours and put another 300 hours on it so far. Had bearings go out on one pulley. Great solid mower. Running Gators and like the cut. Would not hesitate to buy another one.