Which is better?

If you want a high quality good package deal on blast wing and bulb, check out htgsupply.com they have good digital ballasts or lumatek if you want to bundle with them.

k ill check it out so what does the ballast actually do?

The balast converts your 120v household power into enough power to run your bulb that pulls a lot of wattage.

so a digital ballast does it have to be set at some level or do you just hook up the ballast and set up the light and your good to go?

yo ballast ignites the bulb sparks it
no ballast no hid
ballast and bulb are dedicated to wattage