We just purchased a 60" Cat 1 dethatcher from CMP attachments. I'm pretty impressed with how its worked so far. The 3 point puts just enough down force on it that it scratches the surface enough for overseeding and it's real handy to be able to get to the end of a row and just raise the arms to get the thatch out. The only other experience I've had with a dethatcher has been the pull behind type that uses a couple of blocks or weights to apply pressure. This lawn has several large dead spots, that are almost at the point of just needing tilled and re-seeded. I talked the client into letting us try out the dethatcher first and if they water property, let's see what kind of germination rate we get with just that. They weren't too excited about wanting to do a total renovation, but they do want grass. So... short of having a silt seeder, I think this is about it.