Her Demonomicon is causing me great amusement in our current campaign... the party do not want to give it up, but the frequent *visitors* are relentless..
And as many of us old grognards have fond memories of slaughtering hapless PCs in that classic module, which was the ultimate old-school menagerie, I'm not surprised she did well in this 'Survivor'.
Note - Iggwilv herself wasn't in that module, but some of her artefacts were, and so was her daughter - and she made for a magnificent final battle.