Abelf: Haha, Wargotha, not bad! I only tamed Wolves until now but I'll definitely get a Warg next time. I found Lurkers weren't bad either. They chain attacks at a very good rate and they often manage to interrupt foes. They work well with you backstabbing.
NoNewTaleToTell: Interesting, I haven't tried to tame a Lurker (I'll have to try that in the future!) but Crocodiles are fairly useful as well, in my experience. I've tamed Lions too, that was a disappointment! I wonder if you could tame a Shadowbeast...
Nice! I know Ogres cannot be tamed. I tried Mine Crawlers and they're tough as hell! I used one to tank two Ogres. Not as strong as human companions but still. Due to their large size, they can also prevent foes from moving to their target. Only problem is they sometime turn against you. I think if you hit them with projectiles.
ThomasD313: Hmm, I have already 3 playthroughs and many starts without finishing the game and never experienced that Wargs should be that strong. I usually stand ouf of their way until I could easily beat them and never used taming at all (I prefer skills that work in any situation). Also the stunning is as far as I remember less of an problem the further you develop your character (dont know which attributes helps you in this). Another way is to kill them just before they can get close enough (as a Mage or an Archer).
Other strong enemies: Crowds of Orcs (Nordmar), Dragons, Trolls, Ogres, did I forget about some?
Taming is an extremely useful skill! There's no duration limit to it so it's an additional companion! Since this game is about survival, it really helps! Especially on the more challenging difficulty levels.
Granted, you could use a scroll and heal the beast. But you wouldn't be able to use teleport stones since it causes them to leave group.