I'm about to harvest my second grow in hydro. One set up uses (2) 300W LED's, 5000K. Cheapos from Amazon that seem to work very well. The other set up uses a 315 CMH.
I would change to all CMH if I didn't already own the LED's. Heat has to be dealt with using the CMH, but I like what appears to be the penetration and the way the girls responded to it.
One 300W LED might leave your plant(s) asking for more light. I started with one and wasn't impressed by what I was seeing on the first grow, so I added the second LED and things picked up.
Good luck.