I cant speak to Tim Kennedy as I have never shot with him. I can tell you personally that Aaron Cowan (Sage Dynamics) is a very good instructor. My short list of instructors that I have learned most from are Aaron, Jared Reston (Reston Group), Chuck Pressburg (Presscheck Consulting), Scott jedlinski (Modern Samurai Project) and Alex and Jay from Ridgeline. I have shot with many more including Haley, VanDunk, Defoor, Costa, Proctor, at SIG and a number of others but the ones I mentioned really stand out. One of the best was Ron Avery who I got to train with a couple of time but unfortunately he passed a few years ago
Chris