Not trying to start a debate but SF4 and RE5 have sold better on PS3. I know it's only 2 games but do you think future multiplats like Prototype will sale better on PS3?

I'd say yes......but not by a lot

Prototype no cause it has a direct contender on PS3 and not on XBox360.
If the games sell well in Japan, they probably will outsell the Xbox360 version WW. That's what I have observed.

dude, will SELL better. SELL better. Not sale better.

I think you can expect some franchises like Final Fantasy to sell better on PS3, but it really depends on the game. Shooters usually sell better on 360, while racing games do well on PS3.

prototype will sell the most on 360, mainly because this is a game targeted towards americans/europeans, not japanese people.

I made a comment in the past days which fits perfectly to your OP:

It simply depends on the genre:

Japanese games will sell better on PS3. Partly because of sales in Japan and partly because the userbase likes those games better.

Western-Mature games will sell more on 360.

The 2 games you listed have an extremely long legacy on PS hardware and appeal more to the PS fanbase. So your argument has no merrit, unless you can elaborate with better reasons.

delusional

an idiosyncratic belief or impression that is firmly maintained despite being contradicted by what is generally accepted as reality or rational argument, typically a symptom of mental disorder

          This.....:)