I would consider the main difference between RWD and AWD to be the center diff. In either setup there is no guarantee that you have an LSD or locking diff in the front or rear. Thanks to ABS and stability control being standard on all new cars wheel slip can be limited by the ABS system even without a mechanical differential solution (obviously up to a point). There isn’t going to be a best configuration because each type of environment iis different. A setup with locked front and rear diff and a standard transfer case would give you power at all 4 wheels all the time. But that’s going to be hard on tires and drive poor on pavement. Subaru’s AWD setup with the addition of an LSD diff would probably be the best mix between off road capability and drivability.
