Quote Quoting cbg
I'm glad you enjoy them.

This is not a joke: You can google this question as easily as we can. They all claim to be the best and most prestigious so you can eenie-meenie-minie-mo with the best of them. Why should we do it for you?
So you have noticed that a Google search is useless in this case?
It really impresses me. Not only you make very funny jokes, you're also insightful.

A Google search does not help finding names of the most prestigious PI agencies, and this is why i came to a forum dealing with law: Many lawyers work with PI.

I'am not asking you to make my homework, i'am asking people working with PI(google is not help).