My main complaint about Ripcord is that it's non-FOSS, which is somewhat concerning to me (the price is a non-issue; I'd be happy to pay the $20 if that comes with source code access). Sure, Slack itself ain't FOSS either, but I'm more inclined to make it as FOSS as possible (e.g. via Rambox or in an actual browser like Firefox) than to switch clients.

It also doesn't seem to acknowledge my starred channels; while the bookmarks are better anyway, those don't carry over to my phone or my other computers.