Depending on your budget, at the low range a JD with catcher system, there're cheap, but they do the job. We had a catcher version for work, lasted 12 months, just could'nt handle the work and the different opperators...typical local government parks and gardens department.
If you have a look at a mag at the moment which comes out with adds for second hand commercial mowers, you may pick up a bargin.
We have a Walker
www.walkermowers.com.au/ for work and we use it for the Cemeteries...not bad, good pick up in dry and wet grass, easy reg maintenance locations, but it will set you back 15K, but if you can pick up a second hand job with good hours and maintanence, you never know, you can get extras like a chipper and such.
Its horses for course, have you looked at a Mulching deck option?
Anyway check this site or similar...you never know?
www.hewlettequipment.com.au/used.htm