to be honest i think the Nikes are cooler looking, but i have heard from someone who uses them who says the toe on them is thicker, and they don't have a great touch. Where as many people use the F50's so they must not be too bad.
I think for me i would go with the nikes. For one i think they just plain look awesome, and for me I have found that I like the feel of Nikes shoes more than adidas.
plus it shouldnt take too long to get used to either of them.