I have used them before. They are decent, but there is definitely better quality out there, for quite a bit less. Check into the PFO 4 bulb VHO retrofit kits. Not only do they utilize better internal ballasts, but you can also control the lamps for a sunrise / sunset effect, and they also have the VHO endcap mounts with them already, so you don't have to use those cheap T12 clips which seem to fail somewhat frequently. Most any major online reef store will carry the product. HTH