We've done ok with our own servers (I think), but I've heard gmail works well too (assuming the volume isn't too much). - Paul Buchheit

I am getting a little frustrated with keeping our IPs off of various spam filters. I am looking at selectively using authsmtp for some particularly sensitive destinations and am running into problems with our domainkeys verification when relaying mail through authsmtp.com. Anyone encountered similar problems? - Arvind Sundararajan