What does the company do well? Being able to set up lots of channels; filesharing is simple; lots of other programs plug in with Slack without problem; easy to set up group conversations.
What does the company not do well? All the channels, all the private conversations, all the noise. It's too easy to abuse Slack to have back-channel discussions and make decisions without informing the appropriate people. This isn't necessarily a problem of Slack's, but there's not an easy way to limit all the private conversations to make things more open.
What do you wish you had known about the company before using? We were looking for an easy way to communicate within the studio and switched over from Skype to Slack. Since doing that, it's generated more noise and has become increasingly difficult to parse through the channels to pull out the information that we need. We're currently in the process of looking for a Slack replacement that is more feature-friendly to what we're trying to accomplish.