According to a scientific study on PubMed.org, Acai Berry Juice has less antioxidant value than pomegranate juice, Concord grape juice, blueberry juice, and black cherry juice.

But the one that really struck me was the fact that Red Wine tested higher in antioxidant value than Acai, (the supposed miracle berry and "highest antioxidant food in the world).

The study used three different methods to look at the antioxidant value (prepare for science-speak):

1) four tests of antioxidant potency [Trolox equivalent antioxidant
capacity (TEAC), total oxygen radical absorbance capacity (ORAC), free
radical scavenging capacity by 2,2-diphenyl-1-picrylhydrazyl (DPPH),
and ferric reducing antioxidant power (FRAP)]; (2) a test of
antioxidant functionality, that is, inhibition of low-density
lipoprotein (LDL) oxidation by peroxides and malondialdehyde methods;
and (3) evaluation of the total polyphenol content [by gallic acid
equivalents (GAEs)

Here are the results from the study in order overall antioxidant potency:

1. Pomegranate Juice
2. Red Wine
3. Concord Grape Juice
4. Blueberry Juice
5. Black Cherry Juice
6. Acai Juice (the key "miracle component in MonaVie)
7. Cranberry Juice

Another interesting quote from the study:

"…there is also consistent clinical evidence of antioxidant potency for the most potent beverages including both PJ (Pomegranate Juice) and red wine."