Honestly, why do PS3 owners ignore high quality titles like Ratchet and HS? They should be thirsting anything good, but they're letting down the exclusive games instead...
Outside of the SDF running around forum to forum, majority of the PS3 owners are also 360 owners and tend to pick the 360 games. Anytime there is a PS3 exclusive, there are also 360 games available that may prove more desireable due to many factors. For cross platform, we know that story by now.