I'm a bit of a fast walker, or at least my wife thinks I am. From my room at the BWI last month it was a 12 minute walk to MGM, and 5 minutes to the International Gateway at EPCOT.
My favorite things about the EPCOT resorts are the activity. Nice restaurants, active restaurants, activities, and nice pools. They also allow quick acess and return to 2 of the 3 traditional parks. It's very nice to walk out of your room at 8:45, walk in MGM at 9:00, do what you want early, then walk back to your room at 11:00 where you can relax.
Although CBR is an EPCOT resort, it's location is no more convenient than any other resort on property. You can walk to the Boardwalk from CBR, but it's not convenient, and requires you to cross one vary busy street (there are traffic lights, and a sidewalk all the way to the fire station from the Boardwalk). You end up relying on bus service, which can be spotty. The CBR is a nice moderate resort, and I'm sure even nicer since room and court refurbishment, but it's not the same as the Boardwalk, Beach Club, and Yacht Club for access to food and fun.
Good luck with your planning and decision.