I just received my brenthaven Pro 15/!7 backpack for my new 15 umbp, i gotta say im quite impressed, the build quality is top notch, the laptop compartment is top notch, and my vyper m3 sleeve fits in it like a glove, there is ALOT of room for stuff, i haven't filled it up yet, but ill let you be the judge according to the pics, also, in the vids on brenthaven they place their laptops in their bags and drop them from certain heights, and apparently the laptops are 100% protected (zero impact) well i tried it, obviously it was inside the vyper m3 sleeve then i placed it in the backpack and dropped it from nearly 4 feet (average drop) and then i checked it out and there was no dents, booted right up. bag retails for 179.99 US but i got it roughly for 78$. Worth every penny.
It is pretty big, i am a husky guy and it looks big on me. but hey you can drop ur precious goods and nothing will happen, worth the tradeoff imo.
Vids of it being dropped:]
http://www.youtube.com/watch?v=_ZeX6Xjv1EM
http://www.youtube.com/watch?v=DXFYA07G5kw