When people ask what Kombucha tastes like I say, "here, try this!".
It's hard to describe without vinegar, and many kombucha virgins aren't into the idea of drinking vinegar. So I just let them taste it and decide. For sake of your question though, I'd call it a tangy, tart, slightly effervescent version of iced T.
For a beer analogy, to me a Tea-Kombucha is sort of like Ale-Brett fermented Ale. I've found people who like sour beers also tend to like Kombucha.