I'm with you. I am AC-DC with respect to packs. What I like is the rig that is suitable for the task at hand. Externals are great, especially for heavy irregular loads, but they do not work as well when off trail, especially in rocky situations. I only tried to use an external once on a trail in Canyon de Chelly. Some of the trails there range up to 5.9s in climbing difficulty, and you definitely don't want to contact the rock with a rigid external frame when you are trying for the next handhold.