Like most of you, I use a gimbal for my 500. I've been looking around for a new ballhead and had narrowed it down to RRS BH-55 and a Markins Q20. The Markins has a video on it's site that shows it handling a Nikon 800 as if it were gimbal-like.
Does anyone use just a ballhead for their longer lenses as opposed to a gimbal? Just wondering.