I would check around your area for the zero turn dealer with the best service reputation and buy from them.
Or bushhog it a couple times a year.I've have a Scag Turf Tiger. 61" cut, water cooled Kawasaki that I bought new in 1999.
Still running like a top.
Clean with air compressor after every use especially the air filter.
New blades every year. I have lots of sticks and small limbs that get mowed.
I don't know about Ferris but there are times I wish I had their front suspension.
If you don't maintain 5 acres as LAWN I would consider just having it mowed once a month saving space in your garage, fuel costs and the maintenance of a big zero turn.