Just wanted to say something here... I think that only the people who have actually tried the fixtures, should be able to give opinions, but since I know that will never happen I will just give mine.
If you have all the money in the world to spend, then why not go ahead and buy the "get what you pay for" fixtures... If you do not, and would like to save some money by buying a fixture that does not have the "name" price attached... I think that the Catalina fixtures are highly moddable, especially the retro fit systems.
I bought a Catalina 8 x 54 watt fixture, and it was very nice like it was... It allowed me to go ahead and have some nice lights, until the time that I could be able to put a little extra into the unit... If you get Catalina's lights then you get bulbs and all... You cant beat that
So, after about a year I decided to replace reflectors and bulbs a little at a time... Here are some pictures of my results
6" below the bulbs
This reading is 6" below the water's surface, and taken from the middle of the right half of my tank
This is 12" below the surface, just under the one above
18" below the surface
@ the Sandbed
This one is still @ the sandbed, but a little bit over to the left from the one above