Newbie enjoying undead, looking for advice

[Aleph]

So I recently have the full game and am enjoying it, but I'm looking for some thoughts on the various undead nations available in the game. I figure that any serious undead strategy requires one of the nations with priests with undead specific spells, so that's pretty much late C'tis, MA/LA Ermor, and LA Pangea. I'm playing as LA Ermor now and they are pretty amazing, particularly in how simple they are for a new player, but I have the feeling that MA Ermor is probably a lot better if run by someone who has some idea what they are doing. Can anyone enlighten me on the pro/con aspects of these nations (beyond the manual). Which is the most lethal in the hands of an expert?