This pack has greater volume to be able to make the most of self supported trail runs. I have used other ultraspire packs and love the fit and smoothness of being able to bomb the technical downhills and know that you won't be beat up by the pack movement. Pockets are in a great location and easy access to water bladder to speed through aid stations in races.
This review was written in the old system and had content requirements that are different than reviews written today.