The coverage is exactly the same as the 250w Geissman MH I was comparing it to. It handles 24x24 without any problems
An 8 bulb t5 fixture is 500+ watts after ballast losses, and about $700 for the ATI fixture, so a $1000 difference between that and two X30w new. Oh, it doesn't come with bulbs, so $860 new (8* cheapest bulb on BRS), and $840 difference.
200w difference @ 12hr/day is $150/yr at national average electricity prices - which puts us at 5.6 years payoff. Which is a long time. But that's not accounting for another $160 a year in bulbs.
Which puts us a 33 months before the LEDs have completely paid for themselves and you're paying an additional $310 a year to run T5s.
Even with *ridiculous overpriced* LED fixtures (and yes, all the big name LED fixtures are ridiculously overpriced) they're still significantly cheaper than other lighting options. You could buy brand new Radion xr30w fixures at $900 a piece every 3 years and still be cheaper than running 8x54w t5s.
(and crap - forget the blackbox lights - they probably pay themselves off in 9 months)
its just all up-front. Which has its costs (like inflation, time value of money, etc).