Other than the fact they are junk and i am amazed exotera still sells them...
40 to 1 conversion for UVB µW/cm² to UVI (that is an average, just like 6500k color temp is only dead noon)
and panther / veiled min optimal requirements with some D3 suppliments is 30 µW/cm² at the cham hangout zone. Outside summer noon light is about 300 µW/cm² in america.
It doesnt matter who makes them, the sub 200 watt self starting metal halides are just junk. You will clutch your receipt, as every 4-6 months the bulb will fail to start, and the warranty is 1-2 years, and pray its not prorated and they just send you a check in the mail for half of what you paid. By the bitter end i had to apply power, and shake vigorously to get them to start.
I do "hear" that the higher voltage EU bulbs from arcadia, combined with a $$$ 120v to EU transformer are pretty reliable.