This is why Camelbak dominates
I have used a lot of hydration systems, camelbak and non-camelbak. There are two things that keep me coming back to camelbak over and over.
1. Non-leaky Bladder
2. Their bit valves - These things have to take a lot of abuse before they will leak and I don't feel like I am going to suck myself into the bladder when I am trying to drink. The wide mouth allows me to drink comfortably, which is a huge advantage if you have ever used a bite with poor flow.
This is the only way to go when looking for a bite valve.