From the Jack Spade website:
Nylon Canvas is designed for strength and durability. The body material is 1100 denier canvas, producing the greatest density between yarns and ensuring water resistance. Structured yet pliable, it is a sturdy fabric that eases with use. The bags are detailed with finished seams that retain their shape and compliment the softened corners. The interior is lined with nylon rip-stop, which is both lightweight and long lasting.
—Large main zipper opening—Front zipper pouch
—Two exterior slide slip pockets
—Top small hidden zipper pocket
—Adjustable shoulder straps and top handle
—Interior computer slip pocket
—Interior organizing pockets
—12.5" x 5" x 15.25"
Available in three colors: black, blue and canvas.
I really like the elegance and simplicity of the Jack Spade backpack. It's an upscale and highly refined version of the basic Jansport SuperBreak backpack that I used when I used in college (see Jansport at ebags). SuperBreak is the number one selling backback in the world.
It's interesting how Jack Spade took the best selling backpack design and created a version that fits his design aesthetic. Functionally, the two backpacks are similar. I carried the blue Jansport with me during the four years that I was an undergrad and it never let me down.
Why spend $175 on the Jack Spade? First, the design is terrific. Second, the Jansport label signals to the world "I'm a college student and I'm carrying a $25 Jansport backpack for my books and my laptop." The Jack Space label screams "I'm a sophisticated adult with excellent taste in design and I can afford a cool $175 backpack."
I own both the Jack Spade and the black American Apparel Nylon Cordura Bag for $42. I strongly prefer the Jack Spade over the American Apparel backpack. See: Obsession of the Day
Finally, here is an interview with Jack Spade in WSJ that is worth reading.