Screenhero engineer here, and currently working with CoScreen. TBH, Tuple adn Screen both seek to re-create Screenhero (and do an amazing job of that!) CoScreen, while using similar technology, has completely rethought the UI from the ground up, and is a huge step forward that the others are going to have a hard time catching up with. Instead of one person sharing their screen, with CoScreen, each participant can share individual windows into a shared environment that feels as natural as native windows. It's a fundamentally different vision for how to do remote collaboration.