Steve,
The Graden's a great tool for firmer turf - no doubt. But I still would like to understand why it takes longer to heal than the 1/2" core aeration does. I was directed by a friend to a USGA article from 2007 that compared, amongst other things, healing time for Graden/verticutting and core aeration. They noted the same thing - Graden takes a lot longer. But their conclusion was that this delayed healing was related to lack of sand back-filling. However, current Gradens allow for concurrent topdressing so that can't be the only reason. Any guesses as to why?