I own a 1500. Mine is the 21hp Kaw 48". I was not happy with it at first ,but I guess we'll keep it. It has plenty of power and is fast ,but does not stripe very well. Changing the oil is no fun. I do like the independent suspension ,it smooths out a lot of bumps. I had a Simplicity consumer Z before this one that actually cuts a lot nicer but is not a true "commercial" unit. For the money the Ferris 1500 is a good mower ,not sure if I would buy another one though.
Well I have the IS 4500 and really like it. The suspension is what sold me. I had a lot of large open areas that were very bumpy and the IS worked great. The cut is very good as well. mine is the 28 hp cat. The speed is good, but I was used to using an extreme dixie that went 15 mph, so the 12 mph that the ferris does not seem as impressive to me. Overall I really like the machine and I demoe a lot of different ones, again the IS is what sold me though.