Tom Browder writes:
I still haven’t gotten around to getting a new MM3 service up and running, and now I’m looking at Sympa.
You might try asking in the Sympa community. I can't speak for anybody else here, but FWIW I don't know anybody who has switched from Mailman to another mailing list manager, although I know a few projects that have switched to forum software. I know a few people who use other products who see no reason to switch to Mailman, too.
Before I go, I would appreciate anyone giving me a good reason to stay with MM (besides excellent support and a welcoming community—one which is a member of an unfortunately small group of such communities).
I can't think of a better reason than that. Mail is complicated and hard, and it's not something that software can handle without human help. If you had trouble with Mailman and your basic setup hasn't changed, you're likely to have trouble with other mailing list managers as well. I strongly recommend that you make sure that you have a good support network waiting for you if you move. (This is not a knock on Sympa, I know nothing about that community, bad or good.)
Steve