[Faceman]

Actually this depends very much on your party.
Twisted Rune was easy for my good party, as I had Machinegune Mazzy with me but a hell when I first did it with an evil low level party.
Generally I think that the fights against other parties (in the Sewers, Samia and most importantely Drizzt) are underestimated too often.
However most of the fights in SoA can be solved without actual cheating by just using "very creative" tactics and exploiting AI bugs. So none of them is real hard. I had my hardest time with Adalon
(I was rushing through the Underdark to get better items fast and encountered the Silver Dragon at very low level)