I did it for the same reason. I wanted the Fast charger so the 10 core was $80 extra. I'd like to think Apple knows what they are doing in regards to providing extra performance for the price.. but after watching some of those reviews it may be that the $80 was a waste for me. If so, that sucks for me but it isn't the end of the world..I got the 10 core because, why not? It's not that much more so I might as well do it.