In fact, it's quite emotional music, more than it appears to be on first sight. Oh yeah, there is yelling, the atmosphere is really dark and the singing voice is low. But there is hope, in every single song. Maybe this is the deepest I will dive in the gothical scene, maybe I don't need to look any further. I don't dare to, afraid of what I will discover on my dark journey to the black spot in my soul.
As I was saying, I smell hope through the banging bass and roaring voice, "LAMPENFIEBERRRR". This band really is an excellent guide, don't let the German language back you off. This language is made for shouting, made for bands like Unheilig. Furthermore, this is the only kind of music that sounds really awesome in German, it expresses anger beautifully. Anger is a good thing, from time to time. Don't forget to be happy, though.
And yes, ofcourse, as a side note, VNV Nation was around a long time before Unheilig. But VNV Nation is more electronic, and less dark. They're both ambient groups, but both in their own recognisable way.
Give it a shot. Listen to it, enjoy it.
But really, do not drown in it.