Zero Turn mowers are good for mostly flat ground, buy if you have to cut slopped ditches a tractor is better. You may want to look at something bigger than a 42" cut Pony. Do have to buy new or is used OK. There are lots of used machines out there that have got many good years left in them. You need to figure out what mower to get for your acreage. Maybe you could take some pictures with your Pony for scale on some of the sloped areas so people can get a better idea of what your talking about and give us more info on your mowing problems. Good Luck