Discord is great but I have intermittent performance issues with it that make it almost unusable in comparison to Slack which never has any noticeable latency.
I can't really give you "more details," I was trying to use Discord with some people and every couple minutes or so the chat would freeze up and then flood with messages. It wasn't just me, it was everyone in the room's Discord doing it, and it really doesn't seem like a client-side bug.
This may or may not be your issue. But I found that the Windows Defender system would start going nuts on files related to Discord. This would cause all sorts of problems (though most of the files involved seemed to be more related to their auto-update system, which shouldn't have impacted the running process... or so I would have thought!).
This is pretty good to hear honestly. Competition is always good for the consumer. This rivalry between Discord and Slack will only make things better for everyone.