just found a site that has tested them on a m57, so obviously they work on a standard ballast..
woot!
and oddly enough, after 3200 hours the output(ppfd) went from 51.8 to 50.8, but the cct dropped from 9269 to 8442. output hardly dropped, but the color shifted quite a bit...actually, shifted to what most 10000k bulbs are...go figure.
I like this bulb. time to buy one