T5's vs. metal halides is allways such a heated debate
Honestly, I don't have any experience with MH personally, and to let you know i've only had a saltwater tank for about 7 months. Some of the other people on here have a LOT more experience than I do; I only talk loud
I decided on T5's because I'm usually not afraid to be an early adopter to a technology and it just sounded so cool at the time. Thankfully I don't have any regrets. Also where my tank's located, there's only 18" of clearance above the tank to the ceiling, so the extremely slim T5 fixture was quite appealing at the time.
If you're wondering whether it's HO or NO, maybe see if you can look at the manual and see the wattage requirements for the bulbs. That would instantly tell you what kind of ballasts are in there.
But, if you're crunching numbers and trying to get the lowest cost unit possible while still having something of good build quality that won't die unexpectedly, go with a PFO retrofit MH setup. Two PFO 250W mh ballasts with two XM 10k bulbs and two 24" pfo reflectors work out to about $550 all together at J&L online (go to the MH retrofit section). If you were to buy that no-name T5 unit, with your bulbs it'd run you about $500 anyways. I'd go with the PFO MH setup rather than the no name T5 setup. You'd have to build a hood or a pendant, but what's a little woodwork at a buddy's garage?
I'm always leary of no-name anything if nobody's bought it yet and given feedback whether it's half decent or not.