I've often thought a service bed would be great for an off road vehicle, because it would use space that often goes wasted (the space in front of and behind the wheel wells on most pickups.) Being able to access needed equipment without having to go into the bed and dig around is another big bonus.
What I wonder is whether a service bed would be rugged enough for, for example, extended driving on washboard roads or very rocky roads where the bed is rattling around. Those utility beds have a LOT of moving parts (hinges, latches, sometimes shelves.) If you think about it, MOST utility beds are used on vehicles that spend the majority of their time on pavement.
Of course the military uses utility bed pickups so they may well be rugged enough.