I brewed kombucha for several months/years and received absolutely no benefits from it at all. In fact during this time I developed Type II diabetes and I attribute some of that to kombucha which contains both sugar and alcohol. In fact the longer you brew it to lessen the sugar content, the greater the amount of alcohol it will contain.
I've also practiced the Master Cleanse and found that I had to stop it because of the maple syrup which is not compatible with Type II.
I was on a Yahoo user's group during my kombucha brewing experiences and they trashed anyone that tried to use anything other than sugar to brew the tea.
http://en.wikipedia.org/wiki/Kombucha
Normally, kombucha contains less than 0.5% alcohol, which classifies it as a non-alcoholic beverage. Older, more acidic, kombucha might contain 1.0% or 1.5% alcohol, depending on more anaerobic brewing time and higher proportions of sugar and yeast