We get all the benefits of StackOverflow - comments, voting system, etc. The familiarity (as most developers have used StackOverflow before) make it easy to use and get used to.
We used to use channels for team questions across the company but it was difficult to look up similar issues and we had the same questions being asked over and over again. Now we have a proper sharing knowledge hub.
Customer Support seems adequate as well, with a built-in chat for any quick questions.