Well it depends on how much per month you want to spend, etc...AI is great for on the go etc or just to get away from powders. AI is a EAAs and BCAAs. Also, maybe im reading this wrong, but you are asking why take carboslin vs AI? they are different, you need them both. or are you asking AI vs PeptoPRO? for AI vs PeptoPro, its a matter of cost. I get a better fullness from AI though