T5's are much better and will allow you to keep quite a few corals. This includes many soft and a vast amount of Large Polyp Stoney corals. Stocking these types of Coral can create an attractive looking Aquarium. The problem is to achieve enough light you need numerous tubes and this increases the power consumption.
Metal Halide is the brightest option and allows reefers to keep almost all corals including Small Stoney Polyp Stoney corals that are considered the most difficult to keep. These units start with a minimum power consumption of 150 watts, increasing up to 400 watts. Running these 8 to 12 hours a day can put a big increase on energy bills. At the moment that is the last thing that people want in the financial situation and economy.
The problem with all these lighting options is that they all need the bulbs replacing every 6 to 9 months increasing costs much more. Bad to the environment in more ways than one. The impact on finances lessening our budget for corals and other live stock.
The good news though, now with the introduction of LED lighting we can now have cheaper lighting bills and not have to worry as much about changing units because of their long life span. Up to five years is claimed by Tropic Marin Centre on the new aqua beam. Having just installed these to my Reef Aquarium i can confirm they are really good and have reduced my lighting bill 50%. The overall cost can be expensive to set up, but with less usage of power and no need to replace the unit. I will benefit the savings in the long run.