MH conversion bulb

i have a 400w hps ballast and my first grow is complete. I cloned those plants and not have recently bought a metal halide conversion bulb for veg........what differences can i expect in the outcome of buds????? or does the MH light only help in the veg cycle? THANKS FOR ANY HELP!!!!!!!!

the better the bulb...the better the buds!

denser? or more thc? all of the above?