I would like to just give my two cents about IceCap 250W ballasts. IceCap is a great company and I have used there ballasts exclusively for 5+ years but was disappointed with the 250W electronic ballasts as they are not tuned to run all bulbs. I an other have had problems with IceCap ballasts firing XM's and CoralVue bulbs inconsistantly or not firing them at the proper temperature.
I will say that the DE bulbs are very bright as Josh has said. My 150 gallon tank is 48"L X30"WX24"H and I have replaced my two 250DE setups with one 400W DE setup. But if I had to make the choice I would go with DE bulbs.
-Greg
Greg Houston
360 Reef Farm