We have now deployed mxguarddog for five of our clients and use it on our own exchange server. Out of the box with no configuration it works brilliantly, the quarantine emails are great for the end user.
This system outperforms many commercial spam filters we have sold in the past.
We are using MX Guarddog on a few different domains and love it. It has helped tremendously with keeping our time on useful tasks rather than sifting through SPAM.
It seems to just get better and better as well. I can’t say enough about how much we appreciate the service.