I tried this because I like the idea of a vitamin pack rather than just a single pill, and Optimum makes good products. I haven't tried Animal Pak even though I have heard great things. I have however had Animal Pump, but it was really hard to stomach. Also tried the GNC sport pak and it worked well, but not as well as this one. I take this one once a day before breakfast, its good on the stomach and helps to get maximum results out of my workouts without interfering with other supps. The only negative I found was that the pills were are not coated so you should swallow them quick. Outside of that this was a great product, I will be buying again for sure.