I'm using a 250CMH. Make sure u get the philips alto brand if u do, the 4k color temp one. They have a horizontal and vertical type, so make sure u get the right one if u do decide it's best. Only things I would let you know about them...
1) Magnetic Ballasts only. Digitals almost never work with these unless explicitly stated by the manufacture.
2) Use a no glass, open hood configuration if you can. These bulbs emit UVB which is theorized to increase THC production via a UV protection mechanism.
3) 400 is as big as they go, no 6, no thousand... larger setups require more ballasts/bulbs for same wattage obviously.
here's a link to the HORizontal version
http://www.lightingsupply.com/cdm400s51-hor-4k-alto.aspx