They are not the best bulbs, not many color options or flexibility, but I have run them for a year while I am researching and saving up for new lights (keep getting side tracked by coral purchases ;) ) I am keeping and getting good growth from 15+ different z&ps, 5 different chalice, 4 different favia, 5 different acans, blasto, frogspawn, collector mushrooms (meaning not the typical ones that grow over everything), lepto and 4 difffernt types of montis. I have been reluctant to try sps under them. I have about 6.5 watts per gallon though. My tank has been up for about a year with the cfs.
How many watts is the fixture and will it accomodate 2 bulbs? I like 2 different bulbs as you can kinda simimulate sunrise/set. Can't do that with just one bulb.
Also something to consider is that I think these fixtures are becoming obsolete and so it might be harder to find bulbs or the color bulbs you want in the forseeable futre.