Funny you should ask about the acai berry. I recently bought a jug of V8-Fusion and there was an acai berry one. I came home to look up a little info about this berry (as I do not know anything about it), and I found out some interesting stuff.
I'm sure you can do/have done your own cyber-research, but I thought I would share the sites I used. I found that most sites were biased in their own way/direction (for example, some sites were trying to sell acai berry products), but most information that I found was positive.