I have a 61" Y/K ZTMax. I bought it in May of 99, primarily for the cost reason. It was quite a bit cheaper than most dealers were getting for the Lazer Z, yet pretty similar. I also liked the fact that it had a 2 gallon hydraulic resevoir. I don't guess thats a big deal, but I liked the idea of having extra oil if there were a leak you didn't notice right away.
The mower has been pretty good. I delivers a nice cut and is fast. The only problem I have had with it is a small wheel motor leak, not enough to have added any fluid though. The problem is the dealer I bought it from has gone out of business and their aren't that many around. I don't know what the real future of this machine is. If your dealer has a good history and there are other dealers in the area as well, go for it. It is a lot like the the Exmark and uses some alot of the same parts, so finding maintenance items is not that big a deal.
Let me know if you have any specific questions.