WELCOME to LMF...
All 3 are exceptional commercial grade machines...
I'm partial to Hustler... I would be looking at the Z Diesel myself... but the Super Z is good...
The other two are also great mowers... the new John Deere has EFI some may be a little reluctant to get that instead of carburetor fuel system... but EFI has done fantastic things for every other application, so I would welcome that as an improvement...
Scag also has some very nice features...
You didn't say... What type use are you planning for it?
Regardless of your choice, I can't see much wrong with any of them... So I look forward to hearing about your choice and how well it performs PLUS a lot of pictures.... :smile:KennyV