Although hiking through the Floridian woods with up to a 105-108 degree heat index while carrying enough for 3 days out is pretty much always going to suck, the HiSpeed II undoubtedly helped make it more bearable and left me better off than the others I was out with. If it makes a difference, they had a Mystery Ranch SATL, a USMC issue ILBE, and a Condor 50L 3DAP. Although my pack was the smallest, we were all packed such that we each had around 45-55lbs wet. What seemed to be the biggest standout feature that made carrying the weight easier with my pack was that the HiSpeed II had by far the superior hip belt of the four, allowing me to better distribute the weight between my hips and shoulders (I'm sure the frame didn't hurt either).
Coming from an REI Trail 40, the HiSpeed directly addressed pretty much all of my gripes with that pack and more, the biggest relating structure, compartmentalization, and modularity. The frame and more robust waist belt did a significantly better job of bearing and distributing the weight of my gear. I'm also a sucker for organization, so the 2 upper and 2 lower compartments were perfect for me. It was also nice to have MOLLE/PALS webbing throughout, which actually came in very handy for me since it's how I carried my radio, knife and a GP pouch full of trail snacks on my hips and my tent, and my sleeping pad on the bottom.
While I've only got the one hike with this bag under my belt as of the writing of this review, so far it's been a great improvement that was well worth the money and I look forward to getting to put it to further use.