qualitative text analysis software recommendations?

[Seth Lewis]

Hi, I know there are a lot of conflicting ideas out there about the
best kind of qualitative textual analysis software, but I'd welcome
any recommendations here -- particularly with regard to the pros and
cons of, say, Atlas.ti vs. an open-source alternative like TAMS
Analyzer?

I'm on a Mac but can run Windows XP via Fusion 3.

Thanks,
Seth