You asked for honesty:
I say neither. I didn't even like it on the Subaru before the WRX. I will give a lot of latitude in appearance for something that is ugly, but functional. But I hate items being added to a car that are just ugly.
Now, if you tell me that you are going to be cutting a hole in your hood and that the scoop is going to aid cooling (not that we can even tell if the engine is running hot with our stupid idiot light temp gauge) then I would say go for the STI - it looks "better" than the regular.