A lot of gamers on here saying Infamous Second Son is a better game. Its fair to have an opinion.
Let me just put this here
Metacritic
Infamous Second Son - (80)
Sunset Overdrive - (81)
Both Games seem to be sitting on similar scores slightly favouring SSO. Those saying its better.. well not review wise.
Sony wanted to own the IP and MS didn't which is why the game came out on XB1. The sequel can go anywhere unless MS purchase the rights for the 2nd one.