Bayonetta was developed from the ground up for the 360, to take advantage of its particular strengths and weaknesses. Unfortunately, PlatinumGames was not involved in the porting process, so the PS3 version seems to suffer from more than just minor graphical differences and loading issues.

To my understanding, every single graphical decision that was made with the game was so that the game would run at a constant 60 frames-per-second. To the game's creator, Hideki Kamiya, this was a point that he was unwilling to budge on for any reason. To him, action games are just not "tenable" if they are not 60fps. All of the reports claim that the PS3 version has taken a severe hit in terms of its framerate.

Eurogamer's Digital Foundry goes super in-depth with the differences, but the biggest thing holding the PS3 version back is that terrible performance level. He shows several scenarios where the 360 build is running at 56.0fps and the PS3 is running at only 36.0 or lower. That's a pretty huge downgrade in speed and responsiveness.

Here's the link to the full article: Face-Off: Bayonetta | DigitalFoundry

Hopefully that's helpful in forming your decision. I only currently own a PS3, but I'm actually holding off on Bayonetta until I purchase a 360. The graphical differences (such as muddier textures) don't really matter to me. However, the framerate is something that affects gameplay and the game's overall impact. The game is all about speed and responsiveness, and that is something I am most definitely not willing to sacrifice.