In choosing Slack vs Discord for building a team, working on collaborative projects, and making a discussion area:
At first glance, Discord seems like a more affordable solution. Mainly that it’s designed to be free whereas Slack is designed for a team-oriented pay-per-user system. The language that Slack uses to describe its free plans make it sound more like a “free trial”. On the other hand, Discord has committed itself to remaining free and charging only for cosmetic upgrades.
Slack was designed for teams of professional experts to share files and get work done. It’s a productivity tool. Discord was designed as a communication tool.
If your primary motivation is to chat and hangout and discuss stuff, Discord seems oriented toward that. If you want groups to work together on a project to make something and share data, Slack seems oriented toward that.
The core functionality for both services is the same. They give us chat areas organized into customizable rooms, user roles, permissions, direct mentions, markdown, coding blocks, and private communication.
Discord also gives a better upload size limit, more storage capacity, more message history, and high-quality audio channels where you can chat simultaneously via text and voice.
By comparison, Slack’s main draws are integrations with other business tools. I’ve seen people plug in Github, for example, so that a chat notification appears when a new project commit is made by someone.
Discord is more and more a “social” platform revolving around building a list of friends over a multitude of servers. As a more business-oriented tool, Slack requires everyone who joins your server (“team”) to make a new account. This gives you tighter control over who can join and ensures that they don’t have to share account data (names, friend lists, etc) with anyone outside the team - even if they use Slack for other stuff. Discord uses the same account for everything, which seems like a mild and kind of unnecessary breach of privacy.
While I haven’t seen anyone make use of this, Slack gives you the ability to post/reply in “conversations”. I’m not sure most people will need or want this but it would definitely be handy for troubleshooting in gamedev.tv’s Discord server. Unfortunately, this feature doesn’t exist in Discord (yet).
So Slack has more privacy and the “conversations” feature, but Discord has high-quality audio? Want to chat directly with your teammates? Discord offers audio channels that allow you to simultaneously chat via voice and text.
I think Discord is the better choice if you need a social platform. If you want to chat, or share ideas, or discuss topics, and especially if you have an open-door policy and want to bring others in with casual ease. If you are working on a project and need to output actual work, then Slack may be better.
Working in Discord is a bit like holding a meeting in a restaurant where it’s private-ish but someone else can come in or your attendees can bring guests. Whereas Slack is “behind closed doors” and there’s some additional shared office equipment.