OEM comes typically in a white or brown box. The cooling is typically the same. I wouldn't worry about differences in quality, just you don't get the game bundle, maybe less of a warranty. Make sure it comes with a the cables you need tho, (TV-out whatev), since some retailers use "OEM" as a euphamism for "opened, returned without the bundle, and stuck in a brown box." But if it's the real OEM box I wouldn't worry.