Metal Halide or HPS?

I'm looking to buy a 400 watt MH or HPS what's better for growing? Veg+Flowering?

If you had to get only 1, get HPS.

Ok I have another question: can you use a Metal halide bulb in a HPS system?

"It depends" hehe.

There are digital ballasts that can fire either bulb.
There are also switchable standard ballasts depending on which bulb type you have.
There are also conversion bulbs.
And some people bypass the igniter as a DIY project..

I went digital because it runs smoother power, silent, extends bulb life, fires either bulb, has built in protection in case theres a power outage, runs cool to the touch.
Worth the money to me for all that.

Ok thanks alot! :)

Do Not use a metal Halide bulb in a HPS socket that is meant for an hps bulb.They are 2 different ballast. I have used the hps for veg and flowering,and metal halide for veg and flowering. I'd get the HPS.You can use it all the way through the grow. You could get a swichable ballast and have 1 ballast and be able to use the 2 type bulbs.ONLY IF IT IS A SWICHABLE.

GA GROWN!

I've used both for a full plant cycle. 1000 watters each time. I can tell you you will get nice buds which ever one you choose. Some things to consider. HPS bulbs last longer and put out more lumens.

I use both and they seem to work great in conjunction with each other. For twelve hours my veggers get mh and when my girl comes in from her flower box I use the HPS....so far I haved exciting results.