Farmall140 . . . I considered, but did not buy a PT machine and instead opted for a Ventrac. My big concern was mowing hills. I would NOT recommend a Ventrac for you becuase it simply won't do what you NEED to do, but based on what I was able to find, if you have some steep spots, then I think you should dismiss the PT180. You might even want to dismiss the PT422 based on some comments I've read about low power to the deck while going UP the hills.
I honestly think the PT tractors are amazing units, but if your hills are steep, then the PT425 is probably the better choice for you because the new units have higher wheel torque motors and those should get you up the hills with minimal effort, the extra 3 hp may not seem like much, but that will also be put to good use spinning your mower blades on the uphill climbs.
As I searched for my new tractor I found out a lot about Power Trac units and while I am not an owner of one, I am sure that they are simply better tractors than most. Quirky and proprietary, but excellent machines capable of doing what needs to be done, often better, faster and safer than other machines. I would hate to see you get a machine that won't quite, or maybe just barely does, what you need to do and have you overwork it and prematurely wear it out or find out you should have gone up 1 more size, only to end up disliking the machine that might be your best choice if you had only gotten the right unit.
