Rating: 4 / 5
Since having a hydration bladder spring a leak inside my pack, I have avoided all such bladders. I stuck to simple water bottles until a couple of years ago when I ran across the SmarTube - a drinking tube that works with bottles.
This system means I can sip at my convenience (like a hydration bladder system) without the fear of another in-pack leak.
The system comes with the essential cap with air inlet, two adapter caps for different bottles, a tube, mouthpiece and hose clip. The caps are the key to the system; the hose is standard sized and any normal clip and mouthpiece will work. I have changed mine to us Camelbak mouthpieces and hose clips, as they are superior to those which come in the SmarTube box.
Function with the Camelbak acessories would be a "5", I'm giving it a "4" because of the inferior mouthpiece and hose clip.