I dunno if I want to help because I'm so jealous of the deal you got on that tank...
But I will anyway
Im running two 250 watt 14k with two Sunlight Supply T5's with stock bulbs and Im getting great color and growth. I plan on replacing the 14k with XM 10k for more growth and changing the T5 bulbs to a Pure Actinic/Actinic + combo. The key is getting good par and great color.
I think either set up will treat you right, depending on reflectors and bulb choice. A fail in either area will cost you par.
Check out:
http://www.manhattanreefs.com/lighting (MH Bulb/Ballast testing)
http://reefcentral.com/forums/showth...readid=1440723 (Great thread with the first couple pages on T5 lighting)
http://reefcentral.com/forums/showth...6#post14642916 (Grim Reefer from RC is possibly the best T5 guru out there)