I takes years to really get the most out of a system as we saw with the PS2. I'm only just starting to get the most out of Z80 on the CPC after over 20 years. Writing good multi-threaded code is even harder, and that's required to get the most out of the X360 or any multi-core CPU.
The PS3 is another concept altogether because to get the most out of the SPUs requires very clever design due to the totally separate SPU cores with their own memory and a fast bus which links the SPUs and CPU in a specific order (eg. It's much faster to get SPU0 to send data to SPU1 than the other way around).
I would think most developers would initially find it hard to come to grips with the design, but would get a great sense of achievement when they get the code really working and start to build more powerful SPU libraries. SPUs are general purpose and can do fast maths, branch, call etc. They are well suited to AI.







