I went from a 42 inch Craftsman riding mower to my 60 inch Scag zero turn when Sears stopped supporting my mower. I couldn't get parts for it, so I junked it.
The riding mower was fun to mow with. It was slow, but I had a cup holder, and I enjoyed drinking beer while mowing. The zero turn doesn't let that happen, so there isn't anything relaxing about it.
Besides being a bigger mower with more power, the zero turn was comfortable on side hills that the riding mower wasn't. If it was dry, and I only mow when it's dry, I could climb or side hill anything on my land with comfort. I've slid into my pond a few times, but that's my fault, not the mowers. I know better, but I'm always pushing it and trying to get just a little closer!!!
Since I'm in East Texas, and we don't have mountains, I don't know what it's like to have really steep terrain. But for me, the zero turn is the safest thing that I've experienced for mowing in unsafe conditions.