I do believe joints/blunts are the most efficient delivery system, as all the stuff that gets you high (as well as other shit) gets stuck to the joint itself, rather than a glass bong or pipe surface. That is why the roach seems to last WAAAYYYY longer than any other part of the joint, and probably why I get as high off a small roach as as I do from 3/4 of the other end of a joint/blunt. When the smoke has to travel through a resinous glass pipe surface or a huge glass bong surface or the tube/balloon of a vaporizer, a lot of the goodness gets stuck to the surface area, which is why you can scrape resin off a pipe.
I may be wrong, but my main point is that joints/blunts are more efficient than a bong/vape, although you have to dedicate more weed at once. I personally smoke small one hitter bong hits all day long to keep me sane. But I really like the luxury of smoking a joint all at once, that is my absolute favorite. I voted blunt because blunts are bigger than joints, thus better, amen, jesus christ in heaven