So, before getting this pack I was a little worried about all the reviews, but now that I have it I'm really like the pack. That said, I don't live in a very rainy area (Colorado) and I bike anyway, so when it rains, I don't have the problem with the pooling in the pack. I also took the preventative measure of beeswaxings the zippers to prevent any leakage. If you're worried, just get some beeswax from a health food store, and rub it on the zippers, and you're more water resistance.
As for the packs function; its great. I can fit my uggs (short uggs), sneakers, lunch, coffee, water bottle, two outfit changes, and a laptop and charger. I use this on days when I go straight from work to the gym, and on weekend trips for the most part. It is REALLY deep and a little narrow, which can be nice, because I use stuff sacks for internal organization, so my clothes and shoes can be at the bottom and the stuff I want to access is closer to the top.
Improvements I wish I could make: it doesn't sit up by its self very well at all. But not many back packs do. I wish there was a rear or side entry. I wish the laptop compartment was separate from the rest of the compartment. It works fine, but, I love my laptop, and want it as far away from all moisture and food as possible.