The great thing about a black car is that when its clean, it looks goooooood. IMO, it can't be beat when its clean. The shine and luster is just so deep. On the other hand however, to keep it clean is a full time job. Dust, water spots, etc. just show up so easily on black.
In other colors like platinum graphite, to echo 6MT, its easy to maintain. You can't really see the dust until it gets really bad or someone starts drawing pictures in the dust....what I have noticed on my Z (which is PG), is that even after a clay and wax, the shine just isn't as deep, it doesn't quite have that pop that darkers colors can produce. Don't get me wrong, its nice and slick and shiny, just not quite as much...
I've never had a red car, so its hard to really say. I'm sure it probably sits somewhere in the middle of what I just said. either way, red definitely gets noticed
its pretty much the iconic sports car color. i test drove a red Z and I thought the color looked pretty good. A little bit much for me, only cuz i'm a black/grey/silver person.
Just go with the color that really makes you smile everytime you look at one. Even if it requires a lot of work, consider it a labor of love.