Just this reason alone, is a reason to use the PS3 instead of the 360!
Xbox users can just put it on the hard-drive.
It's also known the xbox GPU is very flexible and works well with its memory,thus why it's favoured in games development.
Essentially making the xbox smoother. The PS3 has a little more muscle,but it's often not used.
In all,they are extremely similar.
Also note: that while PS3 has blue-ray ( more space ) some games require you to install to hard drive,on PS3.
So in that regard it's no different to 360.
But i think both versions of the game will work fine.