Sonic the Hedgehog can run faster than the speed of sound, but chooses not to because of the effects it can do to his environment (besides stopping Eggman, Sonic’s ultimate goal is to save his home, and creating a sonic boom from running too fast will destroy it; what you see in Sonic Unleashed in his top speed bar is just the speed he WANTS to run at). read more
Depends on the continuity. If the game continuity, Sonic, as he's beat them both in Sonic Generations. If it's the comics, Sonic is the low-tier sadly, and it comes down to Shadow and Silver, both of which have challenged Enerjak. One thing's for certain regarding Shadow VS Silver. read more