With PFO MH ballasts u can drive any 250w SE bulb. A couple bulbs I know of seem to look better with different ballasts. Those would be the 65k Iwasaki (H37 MV ballast) and Radium (HQI ballast).
I believe all the bulbs are pretty much good in terms of reliability. You'll probably just want to look into intensity and colour differences.
I just found this in a search...Good luck!
http://metricksystem.com/chris/250wcolour/