Having used both VS Code Live Share, and trying out GitDuck last week for the first time, I'd say it felt like a much more immersive experience than the VS Code Live Share experience.

For VS Code Live Share I kept finding myself opening up Zoom and then in parallel trying to get Live Share running, which also feels somewhat finicky at times. The GitDuck experience felt a lot more complete by integrating at a different level. It also felt like it could eventually be a more suitable experience for things we often do in interviews like try to do coding interviews by combining tools like CoderPad & Zoom - though CoderPad has the nice side effect of preservice links to the interviews themselves.