This is by far the most comprehensive and cheap emergency bag there is, and I don't mean cheap as in low quality. Putting together your own bag with the same, or at least very similar, products will hit you a little harder in the wallet. Besides, these bags leave you quite a bit of room for adding your own gear. I was able to add more paracord, 2 battery cases (AA & AAA), and even a bit of cookware, not to mention my own MOLLE compatible first aid kit.
The ONLY thing I can complain about is that after some light use the backpack started to come apart at the base of one of the shoulder straps. I'm thinking it's a one-off problem rather than a design flaw, as there are thousands of bags like this being used every day and I've never seen one complaint. However it is a bit inconvenient. Still a rock solid bag, even with my bad luck.