> They could really deal a massive blow to slack & other with how well the voices

IME Discord voice quality has been awful, and that's just direct voice between two people; multiple times every session the call disintegrates, sometimes falling out entirely. 'Robotic sounding' is a description often used. I think region (mine's Europe) and server capacity in that region, might be an important factor in the perceived quality of Discord voice. Several times it's been so bad we have fallen back to other options, e.g., Teams.