I'll make this quick: this is the best middleweight backpack I've found for photography so far. It's not the fastest or most rugged, but it's the most versatile and comfortable. Let me explain.
Usually, Kickstarter is a collection of scams and bad ideas for internet virgins to be separated from their money. Sometimes, if you know what you're doing, it's a source for good deals. In this case, Shimoda Designs has established itself as a reliable maker of durable, action oriented camera backpacks. Shimoda decided to use Kickstarter as a "group buy" for their new line of Action X backpacks and mine managed to arrive just after Xmas.
A week before the Fremont hike, I grabbed a Shimoda Designs Explore 40 kit from Glazer's Camera. After transferring my gear from the LowePro to the Shimoda, I weighed it and it came out to only 24 lbs. Once I fully loaded the pack with extra clothes, food, water and the extra photography gear needed, it topped 42 lbs. Despite the extra weight, and with a pair of hiking poles, I made it up and down the mountain with my back in far better condition than the previous 2 weekends.