BRS did do a par test of one knock off light, the main issue they stated was the power supply, very weak and several have caused fires. If I recall 14" above the tank provided the par required for most types of coral. Personally one of my main sources of coral has many tanks and several with all black box setups, he grows amazing coral, looks incredible and is not really concerned with the bells and whistles. At the end of the day it does come down to personal preference, tank layout, environment, feeding and so much more.
I went with Hydra 52's because I found a good deal, they look slick and they give the color I like.