IMO, pro Slack instances are wonderful for searching & good for many different kinds of media, though not mixed media (i.e. you can upload videos, photos, pdfs (and search over them all, including with speech recognition!) but inserting photos into a message is annoying).
I’m not really familiar with Zulip or Discord.
(Also, I’m not sure with pro Slack instances really qualify for (2) anymore)
However, these are all very bad for searchability, archiving, multimedia content, and creation of permanent content of any sort.
IMO, pro Slack instances are wonderful for searching & good for many different kinds of media, though not mixed media (i.e. you can upload videos, photos, pdfs (and search over them all, including with speech recognition!) but inserting photos into a message is annoying).
I’m not really familiar with Zulip or Discord.
(Also, I’m not sure with pro Slack instances really qualify for (2) anymore)