I'm considering replacing my tow behind and small propelled with a large self propelled. I haven't heard much about the older RG85's in the 2wd version. Do they get stuck very easily? Will they climb much slope? Do they steer well without skidding the steer tires? I know they have a lot of HP but how much faster are they than say a 7015 with a more direct drive method,(belt vs. hydraulic) Thanks