Working at the golf course for a while now I've gotten a fair bit of experience on some of our mowers. So I'll start...
John Deere F935: This is our roughs mower. I dislike it. It runs fine, and cuts alright but only if Clint has just recently sharpened the blades. Also, the way the thing is all set up when we take it into the rough and get that 72" deck doing its thing, the machine will shake, vibrate and bounce the hell out of whoever is driving it. Alteast it has a roof for when it rains.
JD 220A: This is a pretty good greens walker. It would be nice if the wheels didn't have to be lined up perfectly to fit on, and also the stand for getting wheels on and off tends to fly up a little too easily and quickly. Another thing I don't like is how it "jumps" when you put it in gear, but you can easily get around that by pushing it a little and putting it in gear while its already moving. Other than this though, I've found this to be a great little walker.
JD 2653A This we use for green surrounds on every hole except the par 3s, with which we do the whole rough with this machine. I find this to be a nice machine. It runs good, cuts decently, and the rollers at the back of each of the 3 decks make great stripes. However, its a real pain getting on and off this machine, and I find having my legs sitting up like that they get pretty stiff after a while. As long as you get off and strech often enough it's not that bad though. Gotta slow down for the bumps so the thingys that hold the front things in place don't bounce out of place because if they do you pretty much have to pull the pin and pry it off. Also that parking brake thing got me 4 times today (machine shuts itself off if you hop off without engaging it, shuts off if you drive without disengaging it.) And in transport (atleast with ours) every few minutes you have to pull up the cutters again as they slowly work their way back down. Other than those things this mower is pretty good.
Toro Greensmaster 1000: I don't like the throttle on this greens walker, because it seems really easy for my right leg to hit it while walking along. And its front heavy, so walking with it takes a little more effort than the almost too-well balanced JD 220A. Other than this I have no complains about this walker, seems to be a pretty well built machine.
Jacobsen Greens King V: I like this machine. We use it for tees and collars/approaches, so we use the buckets. It's a pain getting the buckets, but other than this I've never had a problem with this machine. The grip-less tires make hills a little tricky but if you use the right techniques this isn't much of a problem. The parking brake is useless on ours, doesn't do a thing, but as long as you park on the flats the machine will stay where you put it. But as I said, this machine works well for me.