Dont you think you are more likely to have either back or knee problems with a grandstand than with a ztr? you are standing all day bouncing up and down. I feel that after 1000 hours it will catch up to you. You should test drive a Cheetah, they have the best ride of any mower:thumbsup:
I've been going to a chiropractor for years with back and hip problems so those problems are nothing new for me. Before the Grandstand there was never a day I didn't come home and have issues with sore back. I thought the same thing as you about the Grandstand before I took the chance and purchased the mower, I can truthfully tell you I wished I had done it long ago because the issues with the back are virtually gone.
The key to the Grandstand is there Flex-Ride platform it rides better than a ZTR and there's less fatigue during and at the end of the day. Until you use the machine you can't understand how much better things can be and if you ever use the machine for a couple of weeks, as I've been told you'll retire your ZTR and never use it again. At the end of the season I'm looking to replace my 48" ZTR with either a 48" or 52" Grandstand, I like it that much.