I would not trade for a Scag unless it's a hydro, nothing wrong with exmark/Toro. Replace drive belts every season for reliability. Make sure the shift lever is at your knee height and practice shifting(with your knee). Mix a little Lucas oil stabilizer with the grease in the transmission, they shift better. Kohler is a good motor, maintain it well and it will last. Wear anti vibe gloves as single cylinders on walkbehinds viberate the handles.
Forget sulkies, your hands will get a good workout and back down hills and drive up as it's more like reverse assist than reverse. Other than that, when set up right you have a good economical mower that will run cheap for yrs.
I know I'll catch flack for the sulky thing but we have Hustler and Ferris DD walkbehinds and 2 landscaper supply belt drives and belt with sulky sucks when wet/hills/ backing up or with heavy operators.