Bulb cost yes, PC's are more. However the only good ballasts I could ever find made the whole lighting setup a lot more than going with PC's, even in the long run. Now if you had say a Icecap ballast and wanted to decide what you wanted to use, if space is not an issue I would probably pick VHO. For small tanks (I have a 29G) PC's are a lot easier to install IMO. HTH