As impressed and pleased as I am with my Pop Up 28, the new Sawtooth 45 has been calling my name. It's got about 35-40 percent more volume than the PU28, but the big thing for me is that 270* U shaped zipper. For me, that would be my idea of the perfect pack....for now.
Post Script: While the PU28 is just small enough to meet aviation criteria for overhead baggage, The Sawtooth45 might be just outside limits for certain carriers. Although, I've seen people put some way outsized pieces in the overhead bins without being called on it.
