Here is some information about X-Pac: 
"X-Pac® is a brand of Dimension-Polyant, the world leader in manufacturing advanced, high-quality sailcloth. The X-Pac® story is one of innovation and determination. It’s a story that began with a team of passionate sailors and textile enthusiasts — each with equal amounts of grit in their teeth and saltwater in their veins — who saw a need for a better sail and set out to revolutionize the industry. Today, over 50 years later, we are the world leader in manufacturing advanced, high-quality sail cloth.

On that foundation of innovation, we built our X-Pac® line of laminate pack fabrics. Much like a technical racing sail, a X-Pac® needs to perform in the face of varying environmental and physical forces. Our fabrics do that and then some. Remarkably durable with an impressive strength-to-weight ratio and 100% waterproof. X-Pac® fabrics are designed to perform, no matter what you encounter."

Read the content carefully and let me know if this is a good fabric for everyday backpack and if there are any drawbacks with using it for everyday backpack ?