If you're talking the mrp packets, yes I've tried it. I honestly don't really like the taste of it. It's kinda gritty too. A more economical way to go with an mrp is buy a 5lb bucket of chocolate whey, blend it with skim milk and a couple tablespoons of natty peanut butter and there you go: Chocolate Peanut Butter MRP
You'll find this much easier on the pocket book too.