Simply The Best
What more needs to be said here about these great reservoirs that hasn't been said by the previous 98 reviewers? I'll review it anyway, for a couple reasons. First, to give it the five-star rating it deserves, and bolster its overall rating here at Backcountry. Second, to reiterate the versatility of the 100 oz. size, which to me makes the most sense. If I'm going on a short dayhike, I don't have to fill it, saving weight. If I'm on a hike with limited or no water sources, I can top it off. The cost difference and weight between the sizes is fairly neglible; if you're only buying one, get the 100-ouncer.
Also, as I mentioned in my review of the CamelBak Fourteener, the hydration system is better than any other I've used, specifically the main competitor, Nalgene. The bladders don't leak at the hose connection, the bite valve, or the lid, and the bite valves flow better and are more comfortable to use.
I have noticed that when you buy a pack equipped with this reservoir, you get the Ergo Hydrolock valve included; when you buy a replacement reservoir, you do not. No biggie; they sell for about six bucks, but it's good to know when purchasing. All in all, this is my favorite and go-to hydration system for all my outdoor pursuits...