Deere huh? I didn't even put them on my list of potential mowers.
As far as the navigator and walker. How productive are they vs a ztr? I own walker mw's (walk behind) and they are finicky expensive machines. I just had a hydro go on one and it's going to be $1200 to fix it... The other one had to have the pto actuator cradle replaced... $700. I'd like to go with something a little more durable. Speed is important as well as being able to track side to side on a hill. The walker/navigators seem slow and look like they would be very demanding on your body. Plus let's talk about the price... Ouch... $13k?
Make hay while the sun shines!