Other than only 4 bulbs to choose from, VHO does an outstanding job. The actinic white and super actinic are so good, that they are really enough. The internal reflectors get most of the light into the tank, but I always used one big one to help a bit too. They are particularly effective on tanks over 4 feet since T5 does not come in those lengths. VHO is twice the electricity, but also twice the output as a T5 so it takes 2 T5s to equal a VHO. So in a 6 foot tank 4 72" VHO bulbs can take the place of 16 36" T5s with the same output and same electrical costs, but a fraction of the bulb cost. URI claims that their bulbs will last longer than T5 too, which they probably do. I had a GREAT reef under VHO about 15 years ago and I still have all of the stuff. People can do a LOT worse than VHO. If URI would promise to be around in 10 years, I might fire up a 6' 250 with 4 of them.