It breaks down like this...
CELL has slight advantages over XENON (Waternoose), but XENON is more efficient and more developer friendly. CELL' s advantages come down to being able to do more calculations simultaneously and that won' t help the visual output as some seem to think.
XENOS wipes the floor with RSX. It' s next gen architecture and is the most advanced GPU on the market and will be until early 2007. It can render as much of the 512Mb RAM as is required and therefore isn' t bottlenecked like RSX. It would have been nicer to have 1Gb RAM, but console developers won' t mind as 512Mb is more than enough for them. It also has and extra 10Mb of (really damn fast) eDRAM which has been added to specifically handle things like anti-aliasing.
360 has around 13x the bandwidth of PS3 and has a faster drive which combined will allow for quicker load times.
The only thing PS3 has that 360 doesn' t is the ability to output 1080p, -- but who is going to benefit?! Sony' s PS2 install base?! The downside to that is the additional strain outputting in that resolution will put on the unit itself.
So PS3 is bigger which means hotter and louder, it' s not quite as able as 360 and it' s pad has no force feedback, ...but you will be able to play Blu-Ray movies?!
Great. Since most big stuidos are releasing films on both formats, i' ll pay more for the Blu-Ray version so i can play it on my PS3?! Oh wait, i don' t have a HDTV, just a big monitor. My current DVD' s look fine, great infact, ...why do i want to pay more to watch them in HD again?!