I've really only experienced 3 and 4's IPs, but I'd honestly say 4. Quality over quantity.
Quality is subjective though I feel PS3 had both.
I feel like Sony really hit its stride wih 1st party development with the PS3. PS3 brought us great new IP, and greatly improved past IP. This has lead to PS4 being very impressive already, and possible it will end up being the best Sony console for introducing new IP so far.
IMO the creation of SCEWWS, now SIEWWS, is one of the best things that has ever happened in the industry. Since starting WWS, Sony's 1st party had been on a completely different level compared to the rest of the industry, for me. The level of quality coming out of WWS is pure bliss.
I can second that notion, Sony WWS has really hit it out of the park. Someone's opinions on their games may vary but its undeniable that Sony are among the only ones who release bug free and fully functional game on day one without any need for patches and their games are always polished and have fantastic production values. Their studios create games that are different from the norm and popularise them, like GT made simulator racing games a thing when most gamers were never expected to like such a mechanically deep game, God of War popularised mythos based action game that took brutality in games to a new level while delivering scope that nothing else matched at the time along with SOTC, Uncharted bringing Hollywood to video games and Infamous being a game where you can choose to be a superhero or supervillain in an open world that feels like playing an action platformer and requires you to make moral choices. I really like that their developers do something different.