(Bcc; Rick Moen)
Ah, Mailman 3.x
For those that are/were on Mailman 2.x, with it's support having gone away, one of the available logical migration paths is to Mailman 3.x, though that's not optimal for all. Mailman 3.x is a pretty big hairy complex beast, and the archiving and most or all of the web interface bits are split off into separate software/packages.
Nevertheless, at least one data point. IETF - you know, the folks responsible for the RFCs, etc. Well, Mailman 3.x and ... pretty dang slick, impressive, snappy, and very functional. I was pretty impressed, I think thus far probably the best implementation / configuration thereof I've yet bumped into. If one wants to peek, can have a look, e.g. aroun d here: https://mailarchive.ietf.org/arch/browse/acme/ or here: https://mailarchive.ietf.org/arch/ etc.