Dave,
I tried it out with the FEL on (~600#).
I first tried the aerator w/o any weight. It was pulling 3/4" plugs. With the 480# of ballast it pulled 2" plugs out. Might add more. The tractor (18HP) had no problem pulling it, but you could feel the weight in the back. My three point is rated for 1,200# I was at 850#. I could make gradual turns, but not sharp ones. 4WD was needed on hills.
Overall pretty happy with it. Build quality looks good. Paint is excellent. Don't judge by my cheap camera pics.
A couple of minor complaints. 1. No owners manual, 2. one of the zerks was broken. and 3. no top link pin or lynch pins included. The top link pin I have for my rear blade was too small. Luckily I had a bolt lying around that I could use. I don't know if these are usually included, but for a $600 purchase you'd think they would throw in the $5 in hardware. If I was buying at the local dealer I would have just picked it up then.