Only bug I've seen so far is if you perform an action with a hero, then embed him into an army, you can then get the thing to perform an action again while inside the army, but that won't work, however it will un-embed you from the army. Not a big deal, just don't perform more than one action per turn and it's fine, and even if you do it's no big deal. No crash or anything.
Been doing well with Vampire Counts, their early power is really high with skeletons being both pretty decent units and expendable and Mannfred being a fucking beast of a hero, able to nuke other lords, aoe heal his army and melee the shit out of anything that gets close. I've purposefully ignored the cheesy lore and went with vampires instead for undead goodness, overcasting raise dead is great at the start of a fight, the AI just throws everything at it and wastes a bunch of charge and shit, and even if the unit gets decimated you don't lose any army value. Then I just aoe heal and nuke stuff while everything dies.