I'm generally not a fan of red cars. I was considering white, asphalt, and ultramarine when I was looking at FR-S's. I found a good deal on a Firestorm one though and went to check it out. It looks amazing in person, and I fell in love with the color. The only downside I see to the red, apart from being "arrest me red," is that your color options for wheels become a bit more limited. With a car that's white/black/asphalt/even shades of blue you can do the crazy wheel colors thing; it doesn't work quite so well with red.
Unless you're this S2000...
I want a set of teal SSR Professor SP1s or Work Mesiter S1s so bad.