Don' t blame the hardware.
You have to bear in mind that so far there are very very few games that are utilizing the SPE' s properly. Most developers are just using throwing their code at the PPE and hoping for the best.
PS3 is receiving ports. With 360 being the main development platform the game code isn' t exactly suitable for PS3 architecture. So what you' re looking at is code written for a triple-core processor running on a single core general purpose processor with probably some minor operations being handled by the SPE' s.
The problem is that to get the games running like the 360 versions it takes more time (which most of the multi-platform games have already had) and ideally have at least 60% of the code re-written specifically for the hardware, ...but because re-writing the code would take even more time and cost a lot more it' s not exactly feasible for most developers.
Oblivion is probably the biggest exception so far. Not only does it match the 360 version but it exceeds it in several areas, but Bethesda have put in more effort, time and money than the rest of the developers porting from 360 to PS3.
F.E.A.R. is hardly the biggest multi-platform game and i wouldn' t try to judge the hardware by any multi-platform games. We' ve known for a long time now that the best PS3 games were going to be those that were written specifically for the hardware from the ground up.
The issue people are bound to have with it is that more and more game are going multi-platform and until Sony have a proper toolset to deliver to developers that makes porting code easier, then the better versions will likely be the 360 versions (given that 360 is the development platform in the vast majority of cases).
It' ll be interesting to see how Mercenaries 2 will turn out on both platforms because PS3 is the main development platform. Personally i' m watching Epic and their multi-threaded renderer for the PS3 UE3.0