[Rekisito]

The HPS probably will have a higher lumen output than a number of CFL's, but that's something you'll have to check. I would look up how many lumens per plant you'll need to grow a healthy plant. The only thing you should worry about wattage for is how much you want showing up on the electric bill.

Also, keep in mind the price difference. You'll need a balast and reflector for an HPS setup, plus better ventilation.

I personally would lean toward CFL's for a cabinet style grow, since things like heat issues and light placement and whatnot can be fixed with minimal effort. With an HPS it's either get better fans or build a bigger box.

edit: my bad, you already bought the HPS setup, I overlooked that part.