Agreed.
a properly adjusted zero turn mower will cut circles around a push mower, and will cut BETTER to boot.
The grass looks better when there are stripes that are 48, 54, 60, 72" wide rather than a whole bunch of 21" stripes. Plus those little narrow wheels lay the grass down and a lot of times leave little ruts in soft yards like mine.
The problem is, most dealers that sell mowers don't properly adjust the decks and tire pressures, and those that do end up feeling shafted because the owner will run it over curbs and whatever else, and let the tires go flat and just air them up tight without checking the pressures. On ZT's the tire pressures are critical. If one side has 15 psi and the other has 13, the 13 side's tire is a little flatter/lower than the other, reducing the blade cut height on that side and causing cut issues. Secondly most dealers get the mowers in on a crate or pallet, and the decks are almost all set 1/4-3/4" low. That's acceptable by manufacturing standards. However, once one sets the front-to-rear bias to as close to zero as possible, the mower then cuts absolutely perfect, it just takes a little more power to do it and sometimes you need to slow down. On that note, many times what I saw of those complaining about cut quality also were the same ones who were going as fast as they can possibly go, with the deck in the dirt, at part throttle--and the mower just couldn't digest all that grass. It's about like buying a Ferrari and going full throttle all the time everywhere you go--just because it CAN go 200mph doesn't mean it should go 200mph all the time. Same for a mower.
one other thing about any mower-particularly ZT's, I see this a lot. Folks that mow in the same direction every single time. The grass kinda develops a memory and the yard develops ruts. It's always best to change directions every mowing cycle. So if you mowed the yard one way this time, say IIIIII, next time mow it diagonal, say //////, then the next time \\\\\\\. You get the idea. The yard over time will smooth itself out and your cut quality will improve dramatically.