Well the Silver coralife fixture has legs to set it on top of the tank and the black hood does not. Coralife also makes a new hood that has legs to mount it on the tank.
The coralife hoods are only 150 watts though not 250 which is what i would recomend.
The Coralvue hood is $850 while the Coralife Aqualight pro is $740. The Coralife does not have electronic ballasts and the coralvue does as well as a 3 year warranty on the ballasts. Here is a pic of the aqualight pro