I've never been in a shop with metal halides that I liked the light.
t8's with good ho ballasts or t'5s are the way to go I think.
I posted a while back on LED's and bought a Sylvania high bay 11,200 lumens light for experimentation and I don't like it. Big Ass light should be very similar. Very intense to look at it if I'm under the hoist and look up at suspension. Kinda blinds ya and the rest is a directed flood light with shadows. I'm setting my new work area up with t8's with 1.18 ballast factor ballasts and when they figure out led replacment bulbs in the future then I might convert.
Their really isn't an energy savings with the high power leds. Similar watts per lumen, cost is rediculous and the difference would probably never pay for itself.