Since Hagoromo getting Toad Sage Mode is anime only, I'm gonna say he doesn't really count. Other than that I would probably put Naruto as the best Sage Mode user, with Hashirama being a close second because he had some pretty incredible Sage techniques of his own that were capable of fighting Perfect Susanoo's and Tailed Beasts all without the assistance of some other type of chakra, such as Tailed Beast chakra.