Hey, this is my first post. So hello and here is what I know.
Blended Proteins are a few different proteins blended together, such as Whey, Casein, Milk and Egg.
Whey Protein is just whey, it comes from milk.
You want to use two kinds of proteins.
Casein Protein and Whey Protein.
They have different absorption rates. Whey is very fast to absorb, this is what you want to take directly after your workouts, within 45 min. During the rest of the day you want to use Casein because it releases steadily into the blood stream and controls the flow of aminos into the blood.
The blended stuff I have never used, maybe someone else here can help you with that, maybe one of those impressive marketing ploys.