I needed a little added hydration for doing Unbound this past spring. I bought one for the event and loved it. Then I purchased another more recently for my son. I like that I can reach my jersey pockets when wearing it AND there is added space to add some gear or even a light jacket. On hot days I put ICE in mine to add some coolness. (My wife actually puts hers in the freezer).
I have several hydration packs that I use for running and hiking, but I didn't have a specific pack made for bicycling. After researching the pro and cons on the most well known packs I chose this one. I was originally leaning towards a USWE product, but decided on this pack because of the pockets. I use this when I ride in areas or distances where I may have to be fully self supported. The pockets allow for storage of small tools, telephone and food/gels. The straps are comfortable and move with my body. The straps make adjustment easy as the load changes in the pack
The pack stays in place, breaths well and allows me to easily access my jersey pockets. I certainly made the right choice!