Those fixtures are nice for people who have their lighting systems exposed rather than enclosed in a canopy but the cost to import these from Germany makes up for a large part of the price tag. Why would you hide these beauties in a canopy anyways?
As for the "color" the light gives off, it is mostly a matter of taste. See:
http://www.cnidarianreef.com/lamps.cfm for a comparison of different K bulbs. Note that as the temp (K) increases, colors tend to look more bluish. Most PC actinics sold for aquarium use lie in the ~7100K range, while lamps sold for hydroponic use are ~25000K to simulate the color of the sky (VERY blue). Mix and match until you're happy I guess.