I have been lurking on this forum for some time but this is one topic that I feel very qualified to address. I just measured it and the slope that I mow is 25 degrees. I won't spend the money for a Ventrac so I've tried several other mower models in the past. Every lawn tractor that I tried would mow fine uphill but would "ski" downhill because of the upfront engine. I tried a regular zero turn once and could not keep the front end pointed in the direction I wanted to go. I used a rear engine Snapper for years but always felt like it was dangerous because I could never clutch it going uphill. If I did, there was no safe way to get started again without doing a wheelie. I only turned it over once when I was forced to stop on an uphill because of an obstacle. That was a scary incident! After I finally got it to start again, it blew blue smoke for an hour. I promptly decided to trade it in on a different mower. After much research (some on this forum) I opted for a 42" CubCadet RZT-S. This was back in 2012 and I'm still using it. As Gearhead mentioned it is a zero turn with a steering wheel. It is by far the safest mower for slopes that I can afford. I CAN mow the 25 degree slope from side to side without feeling tippy, but mostly mow up and down. The rear mounted engine (22hp) keeps me from sliding downhill although I did replace the stock tires with chevron ag tires. And with the independent hydrostatic drive units I can even stop and start on an uphill without the front wheels trying to come off the ground. So until I can afford a Ventrac, I'm sticking with the Cub RZT-S.