Company switched to it from Slack recently for cost cuts. Generally a huge downgrade of user experience: channel threads are mess to read after a while of being away; no way to lookup/mention other users in private chats; chats and channels is like two separate apps- constant switching between them; activity feed is not always up to date; messages once red on desktop are still left in notifications on mobile; chats list is dynamic - very easy to choose wrong chat by mistake; code snippet editing is unintuitive.