You have lots of options but here in central indy we have most all. Toro,Hustler,Scag... I'm sure your familiar with all of them. If you have a Dixie dealer close you definately need to check them out. Now I know they are a little salty but I know lots of people with well 5-6 GOOD yrs. and still going good. The durability and the speed are well worth the $$ esp. if you have enough accounts to need 2 mowers. A lot of people try to discount the speed and the blade tip speed but until you've mowed heavy(say 10 days growth, it does rain and we all get behind) morning grass you can't understand it but it's there man the power IS there. Don't listen to all about "you can't possibly mow at 9-10-11 miles an hour", you can't but I would pit the Dixie Chopper against ANY mower in the market for all around cut speed and duriblity. So my opinion is at least take the drive(even if it's 50 miles or more)to the DC dealer and try one.
I have not really shopped, but I hear xmark and bobcat are two of the best options. Some machines are obviously heavier and better put together. I'm looking more for durability and comfort than speed and power.
Your best bet is to see what is available in your area and then come back and ask the Lawnsite membership for opinions of what you've found. You're going to get suggestions of 40 different mowers by asking the generic "What's the best ZTR" question.
Your best bet is to see what dealers you have in your area and demo. What works for one member here may not work for another member. I would demo and see who has the best dealer support in your area. What dealer will be most likely to be there after the sale.
check your local dealers first off. the first thing to look for is abundance of inventory that fits your needs. for example, a sears store with an abundance of 42" craftsman mowers and parts will not fit your needs, but a well supplied toro or scag with good trimmers will. second is probably the most important, SERVICE! the best of the most bestest durable machines will break or wear out. who's gonna get your machine fixed promptly and have plenty of parts in stock to do it with will be the question.