I was where you are 5 years ago, with several acres to mow and only a 42 inch Murray. I went thru my Cub cadet phase and this year spent the big dollars on a Ferris Zero Turn. Even after replacing the worn out Intek twin on it that had been cobbled together to sell by some Iowan farmer,I couldn't be happier with the upgrade.
If you have a LOT of mowing to do the older garden tractors can take too much time. A commercial zero turn will cut so much time off that task you'll be looking for more grass to mow.
If you do stick to the Cub line, any of the cast iron rear end tractors will do the job. You'll be looking far and wide to find a larger mower deck that isn't worn out or rotted. If you do find one take care of it and it should last a lifetime. You will also have many different options for add on equipment, and the support of several internet groups specializing in CC tractors.
If CC had made a foot pedal operated hydro, it would be on my list of go to garden tractors. My Murray has a foot pedal hydro and it would mow circles around the 1200 in tight spots. Unfortunately it is so worn out in the deck department I need to find a complete deck assembly or spend a month building a new one.