bought this pack for a recent trip to thailand. i was a little hesitant at first because of the price. was considering other cheaper brands/models (some of which had more space). but in the end, i'm extremely happy i went with the north face. yes, it's expensive, but you also won't find a better built/designed pack.
i was also worried that it wouldn't be big enough for my 10 day trip. if you're packing light (as you should on any backpacking trip) you should have no problem with space; more than enough. i read one review of the bag saying that it was too small - well, this guy was also using it to pack for a wedding. so yeah, if you want to try and pack in a suit, a couple pairs of shoes, in addition to all your casual stuff, of course it'll be too small. but again, that's not really what this bag is made for.
had to take it on a couple longtail boats, ferries, buses\ and 4 separate flights. it withstood thunderstorms, sea air, being burried under dozens of other packs and still came out looking pretty unfazed.
daypack is the perfect size. can fit a 13" macbook along with a camera, books, etc.
i will be using this one for quite some time.