The bladder is nice, strong, bacteria-resistant, and lightweight. However, the cap is really annoying. It's nice that its very large (for easy cleaning and adding things like ice), but it is extremely difficult to tighten correctly. You have to really crank down on it so it doesn't leak, but then it is really hard to loosen again. Not fun when your fingers are cold, I can tell you. It's hard to twist because of the way it is recessed, so you have to use your fingertips instead of your palm.