I agree with e84. Acai berries are just berries, nothing more nothing less. The only difference is they're harder to find and WAY more expensive. Those and goji berries are being hailed as some kind of miracle weight loss foods or fruits that will help you live to be in your 100's Unfortunately it's just not true. They are full of antioxidants, but so are blueberries, strawberries and any other common berry. It's best to eat a wide variety of fruits rather than spending crazy amounts of money for acai products. You're better off spending the extra money on a quality multivitamin and buying organic berries and other produce to reduce your pesticide exposure.
Acai berries aren't exactly a product -- they're a berry, like blueberries, but they taste a lot worse. A LOT worse. They're the new fad in a lot of health foods for their supposedly miraculous anti-oxidant properties. So to answer your questions: yes, acai berries are safe, but make sure that whatever they're combined with is also safe (and not secretly a bunch of sugar, as they do taste horrible).