I had an IIP (pre-06 NB) Matrix for almost 2 years - beatiful color, BUT gets pretty sad looking when dirty, and any touch up work on the paint becomes very obvious compared to black.
I have BSP now, had people comment on how clean my car is when I did not wash it for weeks. After I got in a wreck and showed people some aftermath pictures they kept asking where the damage was. Black hides a lot of things and much easier to color match than "real" colors.
i think its up to you, there is no possible way you will get your answer here. i went with flint mica and am glad, but i could have gone any direction. whatever is available at the dealer is always a good way to decide if you like them equally.