I have a Cheetah with 61" cut and Kawasaki motor. It has 160 hours on it and I am very satisfied. My feeling is you will be happy with any of these combinations. The Cat 2 with the 52 deck seems to be the most common seen on commercial trailers in my area of Texas. It would take up less space on a trailer. My son bought a new Cat 2 last year with the Kawasaki motor and he is pleased with it. Cat 2 is less expensive.
Both of us are just homeowners mowing our own properties. I feel certain some Commercial guys will weigh in.
One knock I have is with the Cheetah 61" you cannot spin off the outside mower deck blades as easy with a impact. The fuel tanks are in the way. Don't know about the 52 deck.