At least from what i could gather the difference is thought at at worst you are just stuck with using the GPU on amd without the switching working properly (that is the case with my new machine), while its unclear whether you are able to use the GPU at all with optimus (or with significant performance penalty). But maybe i'm misinformed about this. It would be more bearable if there was more concrete info about what works and what not. I for example would have been perfectly fine buying Nvidia if i knew that i can simply use the GPU without restriction and without switching...