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

[MikeB]

Some more quotes:

A PC/360 developer responded to this presentation (developer for the PC/360 game Prey):

"Sure you can just about get away with bad code now on the 360"

"Regardless of managed memory or cached memory, the concepts and methods Mike has presented is highly portable. In the case of cached memory, that method results in optimized cache locality and cache utilization (something extremely important when multiple threads are sharing L1 on a single core, and multiple cores are sharing L2), and a predictable way to optimally prefetch. Good data locality, minimal sync points, branch elimination, and vectorization are all required to be able to extract great performance out of the 360 as well."

http://forum.beyond3d.com/showthread.php?t=47057

Nostromo (Neogaf, games developer)

"Using PS3 as a 'lead platform' is the right thing to do if you are going to make a game that has to run on 360 and PS3. The reason is very simple: on PS3 designing your data structure in the proper way is paramount to achieve decent performance (and to scale up..), while your PS3 friendly data will be also 360 friendly data in the vast majority of cases.
This is a big win cause you will definitely be able to get the most from BOTH platforms."

There are more you can find quoted in my Neogaf thread, but I think that's enough for now.