That $100 price difference is a huge selling pointt for the PS4, so there's a possibility that Infamous Second Son might get more sales.and gain more of a fanbase for the Infamous franchise.
I'm leaning towards Titanfall selling better, but can't be too sure. If PS4 keeps selling like it does and the release of Titanfall and Halo don't put a large dent in the PS4 US sales, then Infamous has a good chance.