Back in the day when I worked on golf courses, we only used cam-action aerators (both tractor pto driven and walk behind). I'm interested in starting to offer aeration services and have been looking at walk behind aerators. What I mainly see for sale are what I'll call the "roller" type such as the Ryan Lawnaire. The only "cam action" type that I seem to see for sale is the Plugr. Given the fact the the soil around here is usually pretty hard and compacted, I have concerns as to whether or not the "roller" type would achieve adequate penetration. However, since these seem to be the predominant type, maybe I'm over analyzing the situation. Do the "roller type" tined aerators do an adequate job on really tough soil? or Should I concentrate on a "cam action" type to achieve the best cores?