I got on a CamelBak kick about 2 years ago and purchased their military issue 100oz. Storm and military issue 50oz. Pakteen. They are nice once you have them all ready to go, but with the style I own, it takes some work to get the bladders full, to get the caps screwed on without cross threading, and they are a little hard to clean. I got back from a camping trip last year and they still haven't been cleaned! It's just a pain to clean them and make sure they're disinfected and they take a long time to dry out.
I had problems with the thin O rings that come on the caps falling off. I had them both just fall off twice and they were never found, so I had 2 leaky Camelbaks getting everything in my pack soaking wet. I wrote to the company and got replacement O rings for free. They said that the O rings falling off are not a common problem, but I had the problem with 2 of their products purchased from 2 different stores at 2 different times. Could you imagine being a soldier in the desert and losing the O ring on your Camelbak?
The new Omega style bladders do not have this problem as the O rings on those are larger and are part of the cap. If I could do it over again, I'd buy the Omega bladder, the larger opening also makes them easier to fill and clean, will speed drying time, and the improved cap makes it easier to hold.
Even though I've had a minor problem, their products are built solidly and of really good, strong materials, and their customer service is good.
When I go camping or hiking now, I take a military 2 quart canteen and my MSR Miniworks water filter and leave the heavy Camelbaks at home.