Not bad, but not perfect.
I like the "waterproof" material and zippers. aside from being submerged in water, i think it's true.
i wish the main pocket opened up more- hard to see the pile of stuff at the bottom; have to go by feel.
the little mesh pocket inside is great, right at the top and visible.
it's pretty comfy and stable- better than my 4 year old camelbak mule.
I wish the side pockets came around my hips more so they could not only take more of the pack weight, but also be easier to access. And I have a 31" waist so if you're heftier they'll be further behind you.
Finally, I wish the side pockets had zippers or buttons or something. I've put my phone in during an enduro mtb ride without issues, but it's not very reassuring.
and i think i like platypus bladders more than cbaks. easier to fill and clean with the top mouth opening.