I have the 52" Ferris IS700z. I chose it over the 61 because of some tight places I needed to get in to. However, there's been many time I wish I had purchased the 61" because of all the barbed wire fence line I have to mow under. The extra deck sticking out on the left would have handled that task nicely. I have no problem getting close to the house & sidewalks, the 52" sticks out far enough to get right up next to them. As for the extra wheels to prevent scalping...I think it is going to happen regardless if you have two wheels or four. Once the wheels clears the high spot, the mower blade will probably shave it off.
So far I am very happy with the Ferris, although I am currently experiencing a fuel related issue that is causing the engine RPM to surge. I'm not to happy with the dealers response when I called him today. "Sounds like you got some crud in your fuel system. Run it, it will eventually clear itself out. If it doesn't give us a call back."