I've heard a lot about bladders leaking, but I'll have to say, I've packed a 3l Source bladder all over for about 5 years, smashed elk and deer quarters against it, etc, and never had an issue. I feel if you are going to use a bladder, they are your best bet.I like bladders for the quick convenience of taking a sip whenever but I hate that all of the brands I’ve tried have eventually leaked so I don’t even bother anymore and moved to smart water bottles since they’re light pretty durable and easier to get in and out of the holders on my pack than the nalgenes. I’m going to have to try one of these though. looks like a pretty neat idea and at a reasonable price. I’d really like to see this with a cap that fits a smart water bottle though, that’d be the perfect solution for me.