When I was a HPS guy, I always thought that the DE 1200 watts were the way to go, but it was eventually pointed out to me that I was thinking about things in a wrong way. Actually the best HPS config is 400's, spread out, and button down....
Same holds true for any configs, basically as long as the intensity can hold up. Say if your using quantum LED, you want to go with say the
SF1000D, (their most inexpensive $79 light) because you can button them down, and you can spread them out as far as you like.... make sense now?
An array, always is going to work better... no matter how you slice it.
Then its going to fall to the tech, and the ratio's. ie your diode efficiency, and spectrums.