I recently finished the Mage's College quests. Along the way I picked up two new thralls to replace my current vampire + bandit chief. These two thralls were Estormo, a Thalmor mage, and Ancano, another Thalmor mage.

I've used them as Thralls for maybe 5-6 hours playtime and I have no plans to abandon them anytime soon. They are both very powerful mages, who usually cast Cloaks before battle, a flesh spell and then they bombard the enemies with Fireballs and lightning. Furthermore, Ancano even retains some dialogue as a thrall, which is SO refreshing to have a zombie who says things other than "uhhh... must.... kill".

um.. will they do the dishing?