I finally got my first Nefarian kill yesterday. And my first Ebonroc, Flamegor, and Chromaggus kills before that. Argh, I leave for one month, and the guild goes and gets awesome on me.
This was Convergence's second Nefarian kill, and we did it on the first try. And only about 10 deaths I think (most happening when the Constructs zerged us). Awesome.