I have CoralVue and IceCap are definitely brighter. I have the two side-by-side with the same bulbs and there is a definitely difference. As far as the dimmable one, that one will only work the dimmable part with a certain controller, one that I had heard of before and not any of the well known ones (like profilux, reefkeeper, autonautica, etc.). When I get a few hundred to spare I plan on buying another icecap and just keep the coralvue as a spare for back-up.
Stephen