real McCoy
real thing
real stuff

"It makes a difference when you hear the real McCoy."

You probably can't understand that, since you're the real McCoy.

If this is the real McCoy, you can count me in.

One of them was supposedly the real McCoy, but so what?

But when it came to actually finding the real McCoy, she hadn't been so lucky.

If the guy whose name is on the label answers the phone, you've got the real McCoy.

And no one could tell them from the "real McCoy," as they'd learned early in their schooling.

You're going to have rumors like that when one of them is supposedly the real McCoy.

If this guy is the real McCoy, and really knows people, you're welcome to him.

It is closer in taste and texture to the real McCoy.