S1N1STER, the Ceramic Solutions 630 cmh are great. I've never run them solo, but they kick ass mixed 50/50 with the 600/750 Gavita's. I run the Gavita's at 600 watts.
The room produces less with them overall, compared to the 1k's I had in there, but definitely more per watt used.
I average 1.1 grams per watt with the current lights, compared to .9 grams per watt with the 1k's.