I bought distilled because it had nothing in it, which I thought was good. Then someone said no, that's bad. I posted a question on another forum, and I got an article about how distilled water sucks all the minerals and vitamins out of your body. Then a while later someone posted another article about how it had been proven that that wasn't true. I weighed the evidence, and am finishing the distilled, but buying spring water the next time.
In your case, just talk to the people who've tried it. I myself have only been here a few days, but the worst I've heard of is the cleanse just not doing anything spectacular for some people. I'm on day 3 and everything is going fine for me so far...