This is always talked about. One of the oldest subjex ever talked about it. But honestly, which :was, is, will be...the best shinobi. Like in the early series, Naruto was a little behind, then he got stronger(i.e. Rasengan).
Sasuke has increased his power greatly over part 2, and even survived, emphasis on survived, fighting with Itachi. Naruto now looks like the weaker of the two. If he was able to "control" his kyuubi chakra, then he'd be badass, but right now that isn't the case.
Then there is the rasenshuriken and the kirin question. Which is the more effective. Lets look at that, when Naruto used rs against Kakuzu, he technically killed two people(hearts if you want to use that). Now i do not doubt the potency of Kirin, cuz that looked freakin strong as hell. It is comparable to Amaterasu in power and range(in the sense its unavoidable). But sasuke needs to be outside and has to have clouds above(he wouldn't have had them unless he clashed techniques with Itachi). Naruto just needs an extra shadow clone, that he can pull out of his ass if i might add. The only repercussion is he hurts his arm. So yeah, there's that whole blurb.
Then lets think about future development. Naruto can always use his training to further himself(the clone training). Sasuke doesn't have Orochimaru anymore so thats out the window, but i still see some growth. I don't wanna seem bias but i sincerely think Naruto will be on top in the end. He has the kyuubi(if anyone argues thats not his power than thats a whole different subject), the clone training, and just to throw it in there...he's the fourth's son.
Side Notes- a lot of people like to speculate that Kishi might eventually have Naruto learn the Thunder God technique(teleportation), and learn to infuse his Kyuubi chakra with his WInd chakra. If you want to involve that in this discussion, go for it.