In an article with Siliconera, the Japanese video game makers answered why they have recently changed their stance from making Xbox exclusive games to Playstation exclusives with the upcoming Quantum being a PS3 exclusive;

Makoto Shibata, Director: Japanese development tends to focus and specialize on particular hardware. When we were thinking about doing this we saw the PS3 as the hardware with the highest specs.

I hope they are not the only developers out there that think this and we can see more games using the full potential of the PS3. the rest of the interview can be read at Siliconera.