I have a 1999 or 2000 JD 4500, 4WD, Power Reverser, R4s, with a 460 Loader. The only problems I had was a seal started leaking on the front axle by the right tire (seal wasn't installed correctly- warranty covered it at the time) and had a fuse go out (fuse box is under the steering wheel- mini fuses), and it wouldn't start until I replaced it.
Other than that, regular oil chances, hydralic oil changes and keep the air filters clean and its been almost trouble free (did need to replace the battery after 1.5 years of ownership).
This tractor sat for a year at the dealer lot (they said it was either too big or too small for what customers wanted). I bought it "new" with 3 hours on it. The seat is starting to crack due to the first year of UV rays, now it stays inside.
I think you will like the canopy and the new style loader, not sure about the turf tires- depends on what you want to use it for.
Good Luck!!