This is one of the most durable backpacks I have ever owned!  I bought it for college, because as an engineer I carry around waaay too many thick heavy books.  This bag has been great for walking long-distance with heavy books, biking with heavy books, and carrying heavy groceries home from the store. :D  Could be used as a daypack for short hikes, more comfy than many bags, but probably not as comfortable as a dedicated backpacking bag.  I am a skinny woman, and this bag was able to size comfortably for me, but my 6'2" husband can adjust all the straps for him too.

The hip strap is well made, and padded so that it is actually comfortable with 50+ lbs of books weighing it down.  Can't emphazise how comfortable the hip strap is!

The laptop gets it's own padded compartment in the main pocket, and it is tall enough for 17" laptops. I use it for a 15", and the sides are fine, so I don't know how the sides on a 17" would be, but I expect it will fit fine.  Has a nice clip to keep it from bouncing around.

The second (big) pocket out is for shorter items, but from outside is deceptively large because in fact there is a third almost hidden pocket in front of it.  The third pocket has a size zip entrance, so it's not very good for books or papers.  I don't use it for much except sometimes an extra shirt, or scarf and hat, things like that.  If short on space though, remember it's there.  The outermost pocket is great for pencils, bus schedules, combs, flat stuff.  I use the mp3/cd player pocket for my laptop mouse.

The "suspension system" on the shoulder straps actually has a span of tough elastic in between shoulders and bag.  I think it makes the bag ride softer on your shoulders... but also makes it a little more bouncy.

The rain fly is VERY effective, although when not using it is more heavy than you might think.  I had a hard time folding it back up to fit in it's underneath pocket.  Without the fly, the bag can take 1 hour of medium rain and keep your books dry.  Although the laptop zipper will leak and soak the top of the bag a couple inches down, it didn't reach my laptop because the bag is tall.  Fly is bright yellow, it also doubles to make you somewhat more visible when biking in the dark. (Not reflective)

EDIT: Per a question, Added 2 photos of bag with a single-layer fleece blanket 45"x60" inside. First photo of it in the main compartment, second photo of it in the outer pocket. Still had tons of room for things in the main compartment that way.