XMail Feedback requested

Our NT version of Sendmail is not flexible enough to support SPF checks,
and I don't have access to the source code.

I have been evaluating XMailServer, and so far it looks like it will do the
job. Does anyone on this list have any experience with XMail performance or
it's ability to support external checks (particularly on NT)?

J.A. Coutts
Systems Engineer
MantaNet/TravPro