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.