Naughty-Dog offers help to developers coding on the PS3, easing the learning curve, so programming for the PS3 isn't as tough as it used to be.
The PS3's video card is marginally worse, mainly because it still uses the vertex/pixel pipelines instead of a unified shader architecture and isn't quite as efficient - that's what you get for going with NVIDIA before they pulled the 8800s out of their ass. But the Cell is a great backup, Naughty Dog used it for most of the post-processing in Uncharted 2; the SSAO and DOF are done entirely on the CPU. Skinning and the likes can also be done on the CPU. As Uncharted 2 (and soon KZ3, who's development Naughty Dog is taking part in) shows, using the SPUs for offloading the GPU brings it a step ahead of the 360.
It really looks to me like Rockstar didn't even use any of the SPUs and just programmed it like they would on the 360/PC - use the main CPU for physics and game logic and throw the graphics at the GPU. I saw a video on GameTrailers (I think) that compared the two versions, and they looked practically the same (aside from the 360 one being more contrasted - an effect of it's crappy gamma curve), but I keep hearing people say the PS3 one is worse, so I guess hands-on is the only way to know for sure. Doesn't bother me too much though - I'm no fan of westerns :P. Still though.. it's annoying that in 2010, we're still getting 2006/2007 quality ports.
On the subject of AA, there's a method called "morphological AA", it provides some pretty good results and is done entirely in post-processing via shaders. Runs great too. Here's an example:
Original image.
Jaggy image before applying MLAA.
MLAA image applied to the Jaggy image above.
Since it's run entirely as a post-process effect, it's performance loss is almost unnoticeable. In terms of image quality, it's comparable to super-sampling. The PS3 game "The Saboteur" uses this, and is done entirely on the CPU - the 360 version doesn't have AA. I'm more than certain this technique is going to pick-up soon.
