I used it for a short while, back in 2008 when I was training for 2 triathlons. I ordered a custom blend (very mild flavor, no protein, slightly lower sodium) in the fruit punch flavor. I thought the taste was okay, but the one thing that kind of bugged me was that when I would add the water to the mix...it would get "foamy"...like soap bubbles on top. Sort of grossed me out, because every time I'd see the foam, I'd think I was drinking soapy water...and then my mind would tell me that it was tasting like soap.
Weird, I know...what can I say? 
Anyway...I haven't used the stuff since then. Infact, I still have an almost full bag of it sitting in my cupboard. Wonder if it's any good now?
Linda
2012 Seven Axiom SL - Specialized Ruby SL 155