The Pluggr (sp?) is a cam operated walk behind core aerator. I tried one out at the EXPO in Louisville. It's probably the Cadillac of walk behind aerators. When they tell you the price it'll probably bring a little tear to your eye. But that's what I'd want for a walk behind aerator. I think others are making a cam operated aerator now. They'll climb right up a hill.
If you've never been to the EXPO you ought to go. You get to try out all kinds of stuff. I've been around 10 times.
I never found a ride on aerator I'd buy. I use a 5' behind a tractor. I'm going to have to rent a WB aerator for the little areas because the tractor is tearing them up.