I prefer the hydration bladder in the pocket and have carried mine that way while stuffed in behind bear canisters for the past four-five years. I've worn the print off the platypus but haven't had any other issues.

I usually drink two liters per 6-8 miles depending on temperature and effort expended and rarely need to pull it out - but when I have, it's not been an issue. Usually I only have to pull the rain gear and first aid kit out to get to it (those things ride on top of the load).
"In the beginner's mind there are many possibilities. In the expert's mind there are few." Shunryu Suzuki