I have never liked hydration packs. I found that inevitably they leak, smell and/or taste bad. I bought this because I need something for long hikes instead of water bottles.
So far, This hydration "system" is exactly what I wanted. The product seems durable (although I have only used it 4 times). It can be completely taken apart. The mouth piece can disconnect from tube. The tube can be disconnected from the bag (even when full). The bag can be opened from the end, making it easy to dry.
The best part is the cleaning kit. I can actually brush out the drinking tube, something I have never been able to do with other packs. I find the bag insert incredibly useful. When I open the bag at the end, I can stick it in and it allows for complete and quick drying.

CONS: It still has a little plastic taste that traditional water bottles do not have(but its not bad and may go away with use). The insulation around the tube is more for protection than functionality(I would not use this in the freezing cold). The mouth piece works fine now, but I anticipate that it is the first thing that will break.

So far this works great, better than anticipated. It has not leaked yet. I will update my review if any breaks or leakages occur, but after one month, I have been satisfied with my purchase.

So far, I love this pack

I used this water bladder for a backpacking trip to Havasupai.

Pros:
-Great size: easily enough water for my ten mile hike in 80 degree weather.
-Easy to fill, especially with the plastic handle on top.
-Works great with an in-line filter (Sawyer mini). I had to cut the drinking tube, and then fit the tube over the filter. I was worried it would leak, but it worked amazing well.
-Long tube meant I could keep the bladder in my backpack and easily drink while walking

Cons:
-The drinking piece did not close properly, so I leaked water, especially when I set the bladder down.
-The cap to the drinking piece did not stay on, so if I set my bag down, the drinking piece often got dirty.

I got this for early archery elk hunting and used it for about 40 miles of hiking in mountains for 7 days. I tied paracord around the plastic handle and hung it between my Eberlestock F1 packboard and my spike camp duffle. The bladder did shift slightly in the slider handle and got a little bit crooked after 5 days of continuous use without cleaning, but never leaked. It held up and worked great the entire time. I never used all 3 liters, so after the first day I only filled it 2/3 full, but it was nice knowing I had plenty of reserve water. It was also nice at night coming down with a much lighter pack and no plastic water bottles to throw away. In 85+ degree heat the water stays cool all day, hiking from 5am to 8pm. The water in the hose heated up a little, but soon as you drink the water in the hose you can feel the cool water from the bag flowing. When this is nearly full of water it does make a splash noise if you're moving a lot, which isn't great for hunting, but once the water level goes down more it's fine.

The hose and components are good quality and durable. It's easy to get water out by pulling the lock mechanism out and biting on the valve slightly and sucking. I like how you can completely open one end of the bag by sliding the black piece off which basically crimps the bag shut securely. This allows easy access to the inside for cleaning.

Someone in the Q&A said you can pull the bite valve off by twisting so you can clean the hose and valve easier, but I don't trust doing that just yet, so I've been washing the bag out with soapy warm water and vinegar and running the same through the hose while squeezing the bite valve open. Then I remove the hose and while holding bite valve open with my fingers I blow through the other end of the hose to remove excess water. Hopefully that stops mold growth, but for this price it wouldn't be crazy to buy one every year.

This hydration bladder kicks ass! It's better than the last 3 I've owned, I purchased the 3L. The biggest problem with bladders for me in the past is the nipple, I don't see that'll I'll have issues with this one. This is the best design I've seen to date. I highly recommend it. Thanks wacool!

WACOOL customer service was super awesome in offering me a replacement for my leaky Hydration bladder. The new hydration bladder works pretty well.

Original review "I am giving the product two stars because it really leaked all over the place. I even replaced the cap on the bladder with a Nalgeen cap and it still leaked."