IMHO you get a vastly better situational awareness from a big GPS screen.
I have a Garmin 496 mounted in the yoke (for nav backup and TAWS purposes) and would hate to have to fly with it as my only GPS. It is OK as a "DCT box" for flying a straight line to a specific waypoint, but the map is crap and - partly because you only ever see a small piece of it - difficult to use to see where you are in relation to the printed map. It has a very good battery life though.