@alisha-- Your 'fad health trend' comment about acai berry products might be partly true, because in reality, acai berry juice has *less* antioxidants than blueberry juice. But neither one of these are bad juices, there still one of the highest antioxidant containing juices available.
Both acai berry and blueberry actually come from the same family, they both have antioxidants and all the health benefits that come with that. Acai berry also has some other nutrients like Omega 6 whereas blueberry has anthocyanins which protects the cells.
So, in terms of antioxidants, blueberry is better than acai berry. But overall, they're both good and healthy.