I have a 36" 3-point hitch RYAN aerator. I picked it up used from a Rental Center that was going out of buisness.
My only problem with it is that when I bought it, it hadn't been used for quite a while and all the teeth (I guess that's what you call them) had a light layer of surface rust. As I use it, about half of the teeth pull will plugs out and deposit them on the ground, and with the other half the dirt stays jammed in the hole (holes are punched but no plugging is accomplished).
I have found that the more I use it the more it starts to work properly. I assume that this problem can occur with any of the aerators if they aren't used regularly.
DEALERS: I also found out that Ryan dealers are hard to find; not that they don't exist, they're just hard to find. About 2 to 3 years ago I accidently found that the Kubota dealer in Lebanon TN (outside Nashville) was a Ryan dealer. So I picked up a Ryan sales brochure and used the information to contact Ryan to find out where other dealers were. At that time the Ryan information did not even report the Lebanon Kubota dealer as one of their dealers. Last month I stumbled across another Ryan dealer in Maryville TN (outside Knoxville).
Kelvin