The REI Flash UL (9.4 oz) is a nice little pack. I've been using it this winter on ski and snowshoe day-trips with up to 10 pounds of gear and it is quite comfortable. It's well-built and sturdy, and doesn't show any marks from off-trail brush-bashing. The material isn't flimsy silnylon--it's a heavier version with a grid. There is a bit of padding on the shoulder straps, which are a highly breathable mesh.
I'm actually thinking of trimming it up into a stuff sack (remove chest and waist straps, remove hydration bag/organizer flap, use lighter cords, etc.; the weight saved might be 3-4 ounces) for use as a camp day-pack (just like the blurb says!), although this is heavier than having my brother-in-law carry my stuff in _his_ pack because I didn't bring one ;-)
But for $25, I'll probably buy another to trim up into a stuff-sack/pack, because I think this one is going to get a lot of use as-is. I'm planning to use it for SUL overnights if I can't get my low-volume gear list to fit into my Mountainsmith Tour fanny pack (which is almost a pound heavier; hmmm...).