This is the question that I hear around me those days, not only from people that doesn't know what's the difference between ROM and RAM, but from technology addicted users too.
Why do we need to know the better one? Is there one that is better then this? What has inside one of them and the other one doesn't, that makes the difference on money?
So you must chose between those two, Galaxy S3 and iPhone 5?
Both are amazing devices, both can run even best apps from their app store and market, both have processor bigger then the operating system needs to run. The choice is yours to take. It only depends how smart you want your smartphone to be.