Not to say that I am a pessimist, but, I find it less likely that someone might report a bad experience that they may have had. (eg. a terrible bout of diarrea, etc) I think that the wisest thing that one can do is listen to the knowledge and mistakes of others and draw your own lessons. That saves you alot of time. I hope this does not come across as a flagrant disregard for others opinions (it is not), but, in a survival book that I once read, the author spent a whole chapter on the importance of drinking only water that you would "bet your life on," because it could potentially mean just that. That was his lifetime lesson learned, not mine. I thought it to be a valuable assertion. Maybe it will mean something to you, maybe it won't. IMHO Filtration and purification are cheap insurance.
"I'd feel better if we had some crampons. Oh, what the hell, let's go for it..." — Common climbing last words.