I'm not sure whether the belt is supposed to be worn on the back or the front. I've tried both but have settled for the front. I tighten the belt buckles gradually as the belt empties. The 33 inch long water tube was actually longer than I needed and I have shortened it.
For the first few days of use, the water had a pronounced plastic/rubber taste but this has disappeared now. My first use of the belt was on the South Downs Way where water is scarce, with the exception of water taps every few miles which are invaluable. I filled up at each of these and, the weight of the water being round my waist, rather than my back, I never noticed the weight. I've often wished for dehydrated water to save weight. The Ortlieb water belt is better and is now an essential piece of kit for me. I tend to carry two litres now as a matter of course. I have used it with river water plus chlorine tablets. It was fine, apart from the chlorine taste, but it needed rinsing out several times to fully get rid of the taste. Latterly, I've filled it with, say, river or stream water, attached a Sawyer mini filter and drunk from it. As opposed to, say, carrying a filled roll-up water container, it's not so obvious that one is looking to discreetly wild camp somewhere.
I should say that I use a pack without a hip belt and so the Ortlieb water belt is comfortable. I've tried it with a pack with a hip belt and it's no problem. They don't clash but it may not be the same with all other packs. It depends very much on the individual.
Price – the best price I found (from Ghyllside Cycles of Ambleside) were for the water belt £16.65 and for the optional drinking tube £13.50. I bought these items with my own money.