I think the 360 version will have better legs. Since the PS3 version sold at a higher attach rate it will reach market saturation more quickly. GTA 4 is a game that caters to the type of fanbase the 360 is always accused of having so I think it will see continued strong sales.
The PS3 version will continue to sell as well, but I envision a CoD4 situation where both sell but the 360 version sells more.








