Pretty much this. Like the glycemic index, any insulin spike from protein needs to take into consideration any other foods (carbs, fiber, fat, and total calories) you have at the same time. A whey shake in water vs a whey shake in whole milk with peanut butter on toast, for example.
Metabolic Drive, with slower digesting micellar casein, has been a go-to "meal replacement"-type shake for tons of people. Mag-10, with faster digesting hydrolyzed casein, has been a go-to between-meal shake and peri-workout shake for tons of people.