DT> We are having _really_ good results with SPFv1 so far.
DT> 2 months ago our e-mail was nearly unusable for the spam.
SPF's got practically nothing to do with spam - it just tells you when
someone faked a sender IF the sending domain happens to have SPF in
their DNS TXT records (rare - and even rarer that spammers would pick
one of these domains) - so - I'm guessing you're confusing SPF with
something else?
If I'm wrong - please enlighten me: what on earth are you talking
about? "50% SPF rejectable"??? Are you rejecting people because they
*don't* have SPF records? sounds hard to believe you'd get no false
positives?