i just got two Colormax replacement bulbs (5500 spectrum?) for a double 24" hood I have on left side of my 36" 38g tank, and it gives that side a pinkish hue. On the right side of the tank, overlapping a bit, I have a 24" Aqualight CF hood with a single 65w 6700 bulb and that side is very neutral in hue. So it's a great way to compare the two spectrums, and I have to say, I prefer the 6700/right side of the tank. The gravel substrate in particular looks more natural vs. the left. The latter looks a bit "fake" due to the pink coloration from the Colormax bulbs.
One thing about the Colormax bulbs, though: they do make the color of my fish really "pop." A MAJOR difference. My keyhole cichlids have a slight irridescence when they swim under the Colormax bulbs, mostly around their eyes and fin tips, that I never noticed before. So if you care more for bringing out the colors of your fish, and don't mind your substrate and plants taking on a bit of a pinkish hue, go for the Colormax. Even my (usually) oblivious 16-year-old noticed the difference.
Bottom line, I think spectrum (mostly) comes down to aesthetics, and what you find pleasing to your eye. Very subjective.
One question: is the pinkish hue from the Colormax bulbs due to phosphors they add, or to the spectrum itself?
[Setup update: I just ordered a 96w Aqualight single bulb CF hood (6700 spectrum) to simplify things: using two hoods is a drag. Will be interesting to see if natural hues hold up.]