This wasn't focusing on 1:1 calls, but a couple years ago we tested all the video chat services we could access. We had offices spread across India, Malaysia, a

This wasn't focusing on 1:1 calls, but a couple years ago we tested all the video chat services we could access. We had offices spread across India, Malaysia, and the US with varying qualities of connection and many people working from home. Zoom had the best results when working with a poor connection. I'm not sure I'd say the peak quality was as good as FaceTime.