It's not that these are bad as they are decent fixtures, it's really more a problem of poor quality control. Many times the connections inside the fixture are loose or not connected at all. As far as components go, the fans they use don't last very long or get loud. If you are looking at one of the older units, that come with magnetic ballasts, that's pretty much it. Check your connection and be prepared to replace the fans. On the newer fixtures, they have some of the same issues but it's also been reported that the electronic ballast they come with do not provide the advertised power. There is quite an extensive thread on Reef Central if anyone is interested.