Ask HN: Does a viable alternative to ScreenHero exist?

I've been using ScreenHero ever since I first found out about it a few years ago. They were bought out by Slack and I assumed that meant slack was going to integrate them into their product. I'm sure this is still the plan but after waiting for over a year I'm not sure it will come any time soon. There is a way to invite people to ScreenHero but otherwise you can't sign up since Slack bought the company.

Does anyone know of an alternative that is as usable as ScreenHero? I can't believe there isn't an open source alternative… or is there? I realize that VNC software is very similar but the idea of giving people a username/password to your machine vs sharing a screen with someone in a buddy list is wildly different.

I'd be interested in collaborating in an open source version of ScreenHero if anyone else is interested