I measured one at a frag swap and it was a bit weak, but to their credit given the PAR/Watt Ratio it was very efficient.
Overall considering bulb replacement and AC cooling a MH, $800 is less expensive than your current set up. There are other LED alternatives that are more cost effective with the same or better results.
I have about 500gal total, but main tank is 8ft x3x3 , lit currently by (4)400 wat halides and (2) 6ft vho and (4)t5ho.. hard to justify the money, but i have seen them in person and the shimmer and color pop is awesome