If PS3 is hard to port to, then just make on the PS3 first....read

[Squilliam]

A game for both the PS3 and Xbox 360 cannot generally:

• Be larger than 6.8GB
• Use more memory than the PS3 has available
• Be more than either the CPUs of the PS3 or Xbox 360 can handle
• Use graphics techniques which are incompatible on either. Deferred rendering is one such nono.

Luckily then that they are so similar in performance.