I purchased this to go with my Osprey Atmos 65 pack, in the Osprey, you can hang the bladder between the back panel and the inside of the pack (gives you more space in the pack, however does reduce air flow a bit) after one trip, one of the eyelets ripped as they are not reinforced. if your going to place this in a pocket, it's a great choice as it is super light.

had mine for over a year and it has been on countless expeditions and climbs all over the country with no probs...it is very light and durable...the bite valve is comfy...i've never needed to remove the tube for cleaning or drying and she's working top notch with no funk

I could go on for a long time but I'll make it quick.

Good:
1) Didn't notice any taste

Bad
1) Lid does not easily screw on
2) Plastic hose lining doesn't let you pull the tube off for cleaning or drying. I took it off and now I can't re-attach it because the lining inside the tube gets pushed up and blocks the tube.
3) Resists freezing = not close to true. The mouth piece freezes up very quickly. In getting it unstuck, I managed to break the "turny dealy".
4) Mouth Piece leaks.

This unit has a water tube with an inner liner. This inner liner detached within two days of use, gummed up and created an obstruction in the line. I purchased this hydration unit for a patient with ALS who cannot hold anything in her hands and can barely reach up to grab the tube. She thought she was getting too weak to even drink! It was a waste of money. We are having better luck with the CamelBak.

I put a couple of key rings at the corner and hang it off the back of my pack. Works great. It's tough enough. During one trip when most of the water inside froze, I was able to break up the pieces of ice without fear of puncturing the bag material. Mine is working fine after a year of use. Ridged screw cap great for gripping, can be a little painful when fingers are really really cold. Or maybe I am a just a wuss.

None of these reviews really seem to address the real reason for buying this bladder: functionality. My question to all of these reviews: If you own one of MSR's water filtration devices why would you use any other bladder? Simply screw this bladder onto the filter and away you go. No need for an intermediary devices or extra hoses only to then have a mis-step and spill the bounty of water right back into the muddy pond. Every bladder leaks and you simply need to wrap the straw into a service loop in the locked position and store it without any equipment on top of it. All straws will pseudo fracture due to cold without an insulation sleeve. If you go from filling your bladder at the kitchen sink for 2-hour hike and come back to refill at the sink, then maybe a wide mouth CB is the way to go. Take care of your equipment and don't knock down a product if you don't use it for its full functionality. I have had the same MSR 2.5L bladder for 2 years despite all of the abuse I put it through.

I had planned to take this on an overnight trip, but the mosquitoes convinced me otherwise. Which is fortunate, because I discovered the bite valve had a slow "drip, drip, drip" both in the closed and open position. The connecting hose also had a slow leak. Perhaps I did something wrong, or am just cursed by things that go drip in the night. (I once had a hydration bladder leak form a nice puddle inside my tent). I also found it difficult to screw the lid on and off. Couldn't imagine trying that with gloves on. I'm considering returning it for another brand or just going back to the good old Nalgene bottle.

This MSR bag has two holes in the top which works perfect with my Osprey Atmos Pack. If you are afraid of it breaking, CamelBak replacement parts are available in almost every camping store and can be used to repair to create a hybrid back. If you want a bladder for more rugged use outside of your pack, buy the stronger Red MSR hydra pack.

I have to say this is the worst Hydration bag I have ever owned. I wonder why MSR company is still selling this product. Two big headaches: 1) Lid is very hard to screw on and leaks; 2) bite valve also leaks at the connection point.

I hate this bag. It almost ruined two hiking trips of mine.

inner liner of tube got jammed up in same way as another reviewer. I got a about a season out of it. Couldn't fix and so this bag is now useless. Did really like the bite valve on this; far better than other products.