When i said that 4ft fluoros (triphosphor T8 with electronic ballast) are of similar efficiency than a 400w HPS, i refer to initial output.

I put the output of Phillips SON T-Green Power (one of the best HPS in the market) and of the Phillips fluoros 830. You can see that the photosyntetic efficiency (PUR) per watt are very similar, as well as system efficiency.

And yes, leds are the future, but currently, its efficiency is below HPS. But using only reds and blue, it can be compensated by its better spectum to promote photosyntesis. Use white led dont make sense. You lost the spectrum advantage, have very poor efficiency and last less than 10000h (in fact, if you dont run them properly, they burn out in 3-6000h).