From both a streamer and a techie. Zoom with its paid sub is the best voice video program out there.The encoder for voice and video are top of the line, but because it is made specifically for the enterprise market it lacks some features you might want like a proper push to talk function (it has one but its not configurable to different buttons). In saying that a new update just released a bunch of quality of life features like noise gate, suppression and echo cancellation. Discord is good, but I know it has some issues with quality and drop outs. But it is also the most commonly accessible and feature packed. The encoding is sub par leading to lower end users suffering from latency issues. But again its also free and simple to use. Its built more towards gamers. Hangouts in my experience is great for phones and tablets and It works best when using 4g cell coverage. It is also made for the business market so its feature package is based around functioning with groups of people. But its encoder make voice sound horrible and video can be laggy leading to sync issues. I honestly don't even both with Skype. Its not on the radar. The biggest thing to take away is that due to the increase of users on all applications its going to mean their is problems and most the time its going to be server related or end user. Free options are going to suffer the most, but in the end they are free, so its like looking a gift horse in the mouth if you are going to complain.