What do you run your listservs on?

What do you run your listservs on? Someone recently asked me "I wanted to ask you if you guys ever created or use an email listserv type of application that you can recommend to me. I am trying to replace a Linux box which runs email lists for our company using mailman but I had problems with it lately and I really want to replace it with something more reliable and windows based."

Here is what I told him:

We use Icewarp Merak Mail Server. Runs on Windows. Webbased and windows admin programs. Easy to create lists in. We use for all our lists (including MDCFUG). Enterprise version lets you keep list members in SQL db. We are working on integrating into our CF code for MDCFUG site.

What software do you use for listservs?