Goku at the end of Dbz is :
Stronger : His physical attacks must keep up with his energy attacks seeing as how it takes Multiple Solar System based attacks to even affect his adversary. By the Cell Saga, multiple planetary destroying attacks are laughed at yet punches from Goku and other fighters affect their adversary.
Faster : Not necesarilly flying speed, eventough from Gotenks's demonstration it's pretty obvious that DBZ characters can fly multiple times the Speed of light . But when it comes to fighting speed, they don't even compare. From what Roshi and Krillin did early in DB in a second, to the speed characters fight later, there is really no comparison.
One thing that must be remembered here is that fighting speed =/= flying speed so nobody should bring arguments that just because Superman flew that fast means that he can fight that fast .
Durability : Goku can take multiple Planet Blasting / Solar System destroying attack up to no effect in his strongest form. He can also take a huge amount of punishment and still get up and fight on.
Not to mention the fact that Goku has a vide array of attacks and tehniques which would give him a huge advantage in this fight such as Instant Transmission, Kienzan, Kamehameha etc.