In agreement with others, look at different brands for the proper fit, features and price. In general I prefer Kubota but can't handle the lack of position control on the Bxx20 Series, doesn't bother some though. Kioti, John Deere, Massey Ferguson etc. make good tractors.
My wife won't let a zero turn on the place, so I have no personal experience. Our renters however bought a couple of commercial grade John Deeres a few years ago to use on pond slopes etc and had to quit using them as they kept getting stuck on hillsides, poor handling etc. They went back to tractors and use the zero turns on their rather flat, slightly rolling lawns and ball field.
We will all disagree to some extent on "ideal" size, thing is lots of models will do it, some a bit better than others no noticeable difference.
Now if mowing was all I was going to do and could afford it, my "ideal" machine would be a Kubota F30/3680 4WD with 72" deck.:licking:
Good luck.