Peter,
On GMail, I've yet to receive my first spam message...
I've been using a GMail account for my list activity for the last 18 months
or so. It took a long time before I ever got any spam, but eventually a few
started showing up. But they seem to have a pretty good filtering system
for stuff which never gets through, plus an easy way to report stuff as
spam. My "spam" folder currently has 46 messages in it, none of which are
legitimate but GMail did allow through but put to my spam folder for 30 days
in case I want to review them. So I've had only 46 in the last month, but
*none* of them showed up in my inbox.
I only use GMail for my list traffic though, because I don't care for
Google's rentention policies even with the "do no harm" mantra.
Doug