coralcollector....I too have used the 12k Sunbursts, and they do, unfortunately, suck. The useful spectrum is gone after six months, so they are not cost effective. If you are having good luck with them, by all means, stick with them. Everyone who says they "suck" including myself, are speaking from their past experiences with these bulbs. Also, Blueline, will not warranty their ballasts, if you run the Sunbursts on them...kind of tells you something, huh?
I personally would not recommend them to anyone....my .02