Not going simply by record. Lemieux and Rubio are both legitimate punchers and while they're not exactly contenders, both are good fighters.
I'm not saying GGG has fought tier one caliber guys but when it comes to questions about his chin he doesn't need to fight a big name for us to know if his chin has been tested.
As it stands, those guys I have named are all bigger punchers than Canelo, beyond that however it's a forgone conclusion that Canelo would be the most skilled opponent GGG has ever faced.
As for Quillin, he's decent. Can do a lot of things well but doesn't really excel at anyone facet. Like I said, Haymon is protecting him and his undefeated record. Wouldn't be surprised if Jacobs wins handily.