Longtime BOB dragger here.
Many miles on rail trails, single-track, fire roads and paved roads.
Dragging a BOB does feel IMO to be less efficient than carrying gear in panniers. It might be due to the 16" wheel, but anytime one adds another tire contact patch there has to be more drag.
But for single-track riding the BOB is excellent! Really does live up to the hype about tracking.
Other advantages to a BOB are that you can pull into a campground, unload your gear, and then cruise the other sites for firewood. Or ride to the camp store for a 12-pack. Turn the BOB over and it makes a good table for cooking.
Jim