I too was looking at that odyssea MH light system, until I did a google search for them. Apparently they have been starting a lot of fires due to high temps and cheap wiring. I desided that saveing some money on a fish tank light was not as improtant as preventing my house from burning down. Odyssea was supose to have fixed most of these problems with the 2006 version but its just not worth the risk in my book.
I did buy a 260watt PC light fixture made by odysssea for $126 shipped which has been really nice. Im building a canopy at the moment, Im going to take apart the PC fixture and mount it like a retro in the canopy along with the 175 MH retro kit I bought.
The Odyssea lights are nice and cheap but the MH version is just not worth the risk