Mortis engine is a good second wind for big nasty armies. Coven thrones, Zombie dragons, Morghast, and other high wound count units like to for the heal that go a long way on these units. This unit also does a decent job of tar pitting after you throw the requiary. That said it wont consistantly poor out mortal wounds. One reason being it must activate it's wail of the damned in the hero phase and not in the shooting. It also works well with your mages.
If you bring the mortis engine though bring it with the maligant formation, and then it set up savage level plays.
Coven throne is a Tarpit. While lower leader ship it does better 11+ (where 10 is the highest bravery you can get??) is a 50% chance. agasint most enemits you've got 75% shot to go off. This lets you take troublesome models out of the game. If you fail you move 14" away no problem. Also the throne puts out about as much damage as neferata (ignoring spells of course). Nef gets more rend, but the throne give an extra mortal wound. While, most comp scores put the coven throne at half the price as Nef.
Way i see it if i already have a Vamp lord on zombie dragon or other general i'd take the coven throne for the savings as both would end up doing pretty much the same thing anyway, and the throne would do the tarpit thing much better.
I run both the throne and Mortis engine and things go quite well. Think i've only lost 1 game??? that said i'm new and have only played....14 games???
