Many SHO owners have traded in for either an Edge or an Explorer and are happy with their swap. There are SOME upgrades for Edge/Explorer to improve basic stuff like suspension and brakes. Speedwise, not really that much out there for an Edge especially except a tune. Might do better with the Sport (3.7L/same as Mustang) in that regard. Some Mustang mods like throttle body/spacers are also boltons for the Edge. No downpipes option yet that I know of tho. Exhaust mainly from Magnaflow.
Better cargo room and visibility. Better back row seating.
Same issues with AWD/PTU as the SHO, except not as much power, so much less frequent with the 2011-2014s (6F50 transmission). FWD may be a better choice if AWD not really needed.