I use both for different tasks, but only own the ZTR as 90% of my work involves grass cutting. The ZTR is much faster and more maneuverable around the 60 or so trees, bushes, and flowers that my in-laws have. BTW, I cut not only my farm, but take care of the in-laws farm that includes 2 houses and yards. There are some areas that a GT type works best such as tight spaces that a ZTR will not fit between. This is the case on the in-laws farm with all the trees and yard trinkets that my 78 year old M-I-L likes to decorate the yard with. For the large rough open areas I use a JD 850 tractor with a finishing mower, for which I also have all the ground equipment to do just about anything else that requires heavy duty.
So, the short answer to this poll would be.....use what you need for what ever type work you do. BTW, Snow? What snow?