this has been hashed over many times. the take on it is that according to weber, americans like black. you will find eventually that weber seems to be disconnected from reality at times.
Colors are nice and I'd probably buy an older classic in a color but I like my basic black.
Plus, and I don't know why, but I think the colors would be harder to keep the finish clean.
Being an HVAC Guy by trade and knowing a little about thermodynamics, Black absorbs heat much more efficiently than lighter colors. With the folks in colder climates, it will add some BTU's in the sun (even with cloud cover and snow).
Here in the South, a Grey version would be nice due to solar angles and such.