I've got both ezdrummer and Steven Slate Drums. Both work well and sound good, but ezdrummer is (as the name implies) much easier to set up and use. In all honesty, I ahven't given the SSD program much of a chance. I was fully entrenched with EZD when I got it and being a bit lazy, I wasn't too compelled to get up to speed on SSD. The big selling point, I think, with SSD is the versatility with drum sounds. One can put multiple patches for each drum. They ahve a Three-Snare patch that sounds very good.
For metal stuff, ezd has the DFH expansion pack. If you're looking to make just drum beats, you might not need much else. You would be able to do it all in the computer. EZD has a Solo player that allows you to run EZD as a stand-alone, but I would think you'd want to run it hosted within a DAW, like Cubase.
If you want to do more, then you'll have to let us know what that is so we can offer suggestions.