I'm expecting that one day, this argument will be moot, and LED will have won the war. They have certainly won many of the battles lately... BUT. If you include initial costs in your comparison, T5's beat them hands down. There isn't a coral I know of that you can't grow under T5's, and you can light a large tank at a reasonable cost. Low end LED's just don't work like the high end ones do, and high end LED's initial cost for a 4, 5, or 6 foot tank are seriously over priced. I lit my new tank with an 8 bulb T5 unit... for about $350. If I'd have gone with, for instance, AI Hydra 52's, I'd have topped $1,800 in my initial lighting costs.
T5/LED hybrids are a stop-gap measure... for people who like the shimmer of LED's (or halides), and want the coral growth and coloration that the broad, even, diffuse light that T5's can produce. Eventually, somebody will figure out how to get that broad, diffuse light out of an LED, and nobody will want T5's anymore. They're not there yet, and the closest they've gotten so far is way too high priced for many of us to consider.
