Before we used LSMTP, we used Microsoft IIS and Novell GroupWise (the Internet Agent). Microsoft's product had trouble with the volume of mail from Listserv; it kept running out of threads and then delivering mail to the wrong place. If you have a small volume of mail, it will work. though.
 
 Novell's product holds up much better under load, but it's only practical if you already have a GroupWise installation.

 You can find a rather large list of different mail servers at Wikipedia - http://en.wikipedia.org/wiki/List_of_mail_servers