Sorry I can't help you best types etc but just wanted to say that pre op I bought and tried several and couldn't stomach any so have never used them. I'm eight months out and my dietitian is more than happy with my protein intake.
I know that some peeps swear by them so hopefully someone will be along to help you all soon. X
There seems so many types. Pea, whey, hemp, casein etc etc. Whey seems to be the most common but I wonder whether it's the best!