Yeah, I'm not going to flame you, but I was able to level as Madness without too much trouble. I certainly died more than once (okay well over a hundred or more times), but Khem Val is a big, ugly man who will destroy your foes and threaten to eat you. Plus a Whirlwind that hits three people can work wonders.
Thank you for not making me break out the fire extinguisher
I can see why a Madness sorc could be viably lethal- a Madness assassin (like mine) certainly is. I did go just far enough up the Madness tree with my sorc to get the multiple Whirlwind- it's invaluable.
Since the OP seems to be going assassin: I do advise Madness. It made leveling my 'sin much simpler and has some really devastating stuff higher up in the tree. But whatever you choose, good luck
(meh ahduth- I'm going to respec to Madness on my sorc at 50 just to see what it plays like
you have me curious now)