if your growing in a closet or a confined space, stick with a 400 or less (maybe 6 if big enough.) if your growing in a room with no hight/ space issues, why not get a 1000? however ive heard that running 400 of MH and 600 of HPS (or vice versa depending on growth stage) does wonders for your plant, this just makes things hotter, heavier and more $$. ventilation is the key.

ive gone throught hydroponics.net with 100% satisfaction, only thing is they seem a little pricey. think i might try DH (gee, why does that sound so familar{detention home, get it? lol) and see it those valueline systems run as cool as some. they have awsome prices i agree.