This is right down my alley. I've been a member of LawnSite Forum since 2000 and have owned a couple dozen ztrs since my first Dixie Chopper in y2k. These days, by far, the best zero turn is the one an honest, nearby dealer sells and services.

I'd stay away from box stores with the exception of my local Rural King, they have a fine in house service dept for items they sell.
If you're near Louisville are I can hook you up with one of the USA's great power equipment dealers, Southern Indiana Equipment. They sell multiple brands and are big enough, with 2 interstate hwy locations, that they can handle trailer load closeout deals. They also get much of the demo equip from the annual Outdoor Power Equip show in Louisville.
I've owned Bobcat's best, the Predator Pro and it's great, so is the Hustler Z series, actually they are pretty much all good these days so that's why it's the dealer that is important. John Deere is great but you pay more for parts and maintenance. GrassHopper uses smaller dealers as a rule and they make a quality poduct. Hustler/Big Dog are my favorite mowers, made in Kansas and been in business forever. Parts are readily available and the mowers seem to be designed with service in mind.
As of this season, I no longer mow any yard but my own. I used to do 5, acre sized yards and a 2 acre field but now it's just my own 3/4 acre and I've got the perfect mower for it, the Edsel of the Hustler line-up. Big Dog Power Bar 748, same frame/mechanics as Hustler Fastrack but has the motorcycle steering of the Hustler Trimstar. Did not sell and I bought this new for less than the transmission and Kawasaki engine would bring.

I like this much better than a conventional ztr because it's easy to use one handed, ez on and off and my wife likes to use it.
A word of caution about zero turns. One of the most prominent businessmen in our area was mowing around a small lake on his rural property using a Scag Turf Tiger. The mower slid sideways into the lake, the lapbars pinned him in and he drowned. I've mowed steep hillsides and it's always a thrill ride when they start sliding.
My Big Dog R748
my first one 2000 model Dixie Chopper
my moneymaker BobCat Predator Pro w 1000cc Kawasaki fuel injected engine