Well it's not good to think in terms of "better", otherwise we fall into the same trap as our brethren trapped in The Matrix. Blue and red are the fundamental frequencies. Blue is so abundant and has high energy levels so the plants use a system of blue sensors, called Cryptochromes, to control things such as chlorophyll synthesis, stomatal opening and even phototropism (the direction of growth, or the tracking of the light).
Red is used for various other sensor data. This is referred to as Phytochrome system. Phytochromes are proteins which respond to incident red. Phytochromes have their own special pigments called chromophores, and they change their protein structure based on the specific wavelength of the red. Different responses occur based on the type of structural change of the protein. For example the level of red can tell the plant whether it's in shade and the degree of shading to which an individual leaf (or the plant as a whole) is subject to. So this governs response and behavior, even optimization of nutrient uptake mechanisms. As a result of this sensor data, there will be specific conformational changes such as elongation of stem, leaf shape change and so forth.
So you see it's not a matter of "better" or "worse"... that's an illusion. It's simply a mater of how individual species allocate their resources in response to the environment based on the light provided. If you decide that you love looking at a pink tank then use 100% Grolux type lights and the plants will make the adaptation based on what they sense and will reallocate their resources to match the Grolux. If you decide that you prefer Marine Actinic, or Daylight, or a combination, then the same will occur. As long as you are above the LCP and are providing adequate levels of CO2 for the given photon flux density, the adjustments will be made. Remember that auxiliary pigments have the ability to change the incident wavelengths by absorption and fluorescing. This is easily done by adjusting the energy levels of electrons within the pigment structure.
I can grow plants just fine using standard office bulbs which have most of their energy in the yellow/orange. Osram 840 is a classic example. Here is L. aromatica grown pretty much with these goofy orange bulbs until I couldn't stand it any more. All it does is make everything look orange. What's the big deal?
Here is some more grown with a combination of blue and daylight. I don't see any algae due to blue:
If you want to use the word "optimum" then sure, make sure you have at least some of the fundamental frequencies blue/red, but don't stress over spectral quality. There are so many other things that will have a palpable effect on growth that spectral quality "pales" in comparison. 8)
Cheers,