I've read many threads on this site regarding the zd21, some good, some not so good. Here is my take on the new zd21 pro-deck. I currently own 2 properties, the smaller one with my house on it is 2 acres. I have cut the grass with a JD 240 (4' cut) series for the last 14 yrs. On a good day it will take me 2 hours and 20 minutes. Last week I had the opport. to demo a 2002 zd21. Time to cut was 40 minutes and I stopped to have a quick beer with my neighbor. My newest property which is 32 acres, I cut close to 6 acres of grass. Lots of trees and 2 lakes to manoever around. This spring I purchased a b7800 with a 72" cut and was real happy with the 6 hr cutting time. Well today I had the chance to cut with the new ZD21 pro-deck and cutting time was just under 4 hrs . My newest property is a little on the rough side, so cutting at 10 miles per hour can be a little uncomfortable. It does cut well though. Manouerverablity is unbelievable, fuel comsumption is not bad. I burned about 1 gallon of diesel per hour, at full throttle. If the grass is tall and a little wet it takes 2 passes to cut it real nice. The only drawback to cutting with this machine is that you can't sip a beer while mowing.