Jim, you and I seem to be on the same path in our brewing "careers". Every time you post about moving your process in a certain direction, I always seem to be thinking the same thing!
I'm by far and expert on this subject, but from what I gathered, recirculating mashes allow mash temp to be dialed in and controlled easier, can make a clearer wort, better heat distribution throughout the wort and easier to do multi-step mashes.
I'm just now looking into it and this it what I gathered from people I know that brew on RIMS systems. Just this weekend I was at my LHBS for learn to brew day and they were brewing w/ a Blichmann Tower of Power. It was their first time using this device to control the recirculating mash w/ direct fire and they said it was the easiest brew session they've ever had...although that Tower of Power is not cheap.