I was listening to a couple of Hell's Headbangers compilations, they have 6 available for free on their site. From what I've heard there is mainly Zemial, Profanatica, Destroyer 666, Midnight and Acid Witch, but overall those comps are all pretty good. I'm also waiting to receive a package from them, hopefully will come within a few weeks (there is a limited offer, and you can choose 10 CDs and a couple of stickers for a decent price)