I've only had a problem with 1 liquid but I look at it like this. A - I will never have a problem with any liquid I try. B - I find I much prefer Coke in a glass bottle over plastic. Now I understand that the length of time a liquid spends in a plastic tank probably doesn't even come close to the time it will take to leach flavor but hey every little bit helps. And besides the placebo effect is as real as your mind makes it.
For some reason I think that every time we put juice in the tank, the plastic is breaking down.