It's worked well for me. There was a period where voice video stopped working last year for several weeks and with Jumpgate still in beta at the time we wound up using discord until jumpgate came out of beta. It's been fine since then. If you wind up with 2 players not being able to hear each other they can actually click on the other's avatars and reconnect to them. Not too often in my games, but I've seen it happen. International has also not been an issue. I'm on the West Coast of the US, 3 of my players are on the East Coast and my last player is in Australia. Occasionally there are issues with Australia, but discord had them as well so it's likely more just a bad day for the undersea cables, or as we like to say "The raccoons are messing with the undersea cable again." The top gotcha I see that trips people up is you have to give roll20 permission to use your mic and cam in your web browser. It should prompt for this, but sometimes people don't pay attention or they blocked it forever ago and don't know how to allow it again. It's an easy google search to figure out how to do that for you particular browser. Asides from the permission thing, most of the time when I've seen people blame roll20 when voice isn't working is that their OS is either not picking up their mic or is configured to use the wrong one and because of that the issue turns out to happen in discord as well.
