Author of Aida/Web, Janko Mivšek, created a comparison between three Smalltalk web frameworks:
Janko's post started a heated discussion: Read many of the mails here.
I have only tried Seaside, choosing that framework since it is the “default” one to use for Smalltalk web development. At least the comparison made me aware of Iliad, and had me rediscover Aida/web. I will try Aida/Web again.