Disadvantages to growing solely under 1000 HPS?

....Outside of the earlies stages where they will be under CFLs, is there any reason that I need to buy a metal halide as well? I know the entire grow can be completed under a HPS, but would the results be that much better if i used a MH for veg? I know the differences in light spectra and all, but whos actually done it with only HPS? Thnakle wackies

my grows have been strictly HPS........a 400W
only grow and bloom nutes (no special shit)
get about 1 1/2 ounces per plant at roughly 3 feet tall.

i use 250 MH for Veg and 1000 HPS for flower. I only use the MH because I have it. I would prob use CFLs for veg if I did not have the MH.

bumpness

help meh!

yo man.
i grew with 4x 250W HPS entire grow twice and got pleasing results(soil)
i changed to 2x MH and 2x HPS for entire grow and got similar results.
however....
using 3x MH bulbs(250W) and 1x HPS for veg and 1st week of preflowering, and then switching to all(4) HPS bulbs for the rest of flowering achieved the best results with stax of buds and all of good quality...
hope this helps man...all mine where HPS/MH conversion ballasts so....