I'm looking to get another aerator and have been reading threads about the Plugger and the Ryan which have cam driven tines. Talked to my local dealer and a lot of local people but no one uses cam driven aerators in this area NW. I hear the Plugger has problem with hills and that scares me a little as we are not shy on hills in my area. I did call and receive the promotional info from the Plugger, it looks interesting. So I ask you--- Plus and minus -- Cam vs Drum By the way I am currently running an BillyGoat aerator, like it but would not buy another.