Skeeuk has it right; the biggest problem with "multiplats" is more or less ram control and middleware/game engine. After just playing through Bayonetta's demo the problem with the game is clear: ram allocation. Even though the RSX has access to system ram, it doesn't access it fast enough so you get stuttering problems which is what I noticed in Bayonetta. And the horrible loading is due to that ram problem. Makes me wonder why Sega didn't do a harddrive install which would have fixed a lot of problems with the game. Ultimately, I figured all the games in most dev's pipelines were done with starting on the 360 and moving to the PS3 but I guess I'm wrong. Oh and Skeeuk is right because devs should start on the PS3 to deal with ram/shader issues and keep in mind the 360 so they don't tax the cpu.
Essay Pro