At least on the brightside Kaepernick has arguably the least lofty comparison of the 4some. Wilson to Brees (because they're both short! Get it! Ignoring they have nothing else in common and Brees is an inch taller, yes that does matter) RG3 to Elway (don't see that one at all, I would say more Steve McNair. RG3 doesn't have an otherworldly arm like Elway and Elway couldn't run like RG3 or even dream of running like RG3), and Luck to Peyton (probably because they're both from Indy is my guess)
That said, still have smart money that Luck will be the best of that group, even though the others were more impressive last year, Luck has the more complete package, once the Colts give him some tools to work with he'll start killing it.