Slack - for being unstable (crashes frequently). We have very little noise, so it is only an interruption when somebody actively needs to interrupt me. Skype -

Slack - for being unstable (crashes frequently). We have very little noise, so it is only an interruption when somebody actively needs to interrupt me. Skype - an absolute trainwreck of instability and messages not syncing between devices. Always needs to update - and never improves. I only use it because it is still the de-factor standard for a lot of poeple.