BBL brewer: So far, I've been getting anywhere from 6-12+ oz. of dried cones from each of the Cascade and Chinook plants that are past their first season. Last year, I had one Cascade that kicked out nearly a pound. Now, with another season of stored energy in the crowns, I suspect yield will be a bit higher across the board.
From the pics, though, you can see that the bottomless barrels can become limiting to root growth over time (but not as much as a big pot, which will become root bound in a few years). However, the benefits of pots is that your plants don't have to compete with the roots of nearby trees and shrubs. For me, using raised boxes is a practical necessity in the backyard to keep my roaming tortoises away from the goods.