I swear by mine! I usually end up dehydrated when I don't use it. Using one helps to remind me to drink constantly and as it is right there on your back, no bending or reaching for a water bottle it is very convenient. I use a Camelback backpack which also has room in it for all my other stuff. I did find that mine leaked a bit but I just pad the bottom by the hose with a small washcloth and put the water bottle in a plastic bag. this seemed to solve the problem nicely. Another nice feature is the fact that you can put ice in the bottle so the water stays really really cold.
Give it a try!
Linda