We have:

1. Traditional Distorbution packages. If someone want to go that way OpenSuse Build Service. https://build.opensuse.org/

"The openSUSE Build Service is the public instance of the Open Build Service (OBS) used for development of the openSUSE distribution and to offer packages from same source for Fedora, Debian, Ubuntu, SUSE Linux Enterprise and other distributions.." (Possibly MacOS and Windows)

2. Package Formats (I hope it is the future) we have appimage, flatpak (Redhat backed), snap (Ubuntu backed). Containerized solution with the hope of easier portability and better security by sandboxing type solutions.

Personally I think flatpak is the best of breed with appimage a close second. Flatpak and appimage are the most open friendly. Flatpak using individual repositories which I prefer. Snap uses a central location which i also don't like as much.

http://flatpak.org/

Anybody's guess.

Seriously, .deb or .rpm is okay, but what users will really want is a proper apt/rpm repository, which is for sure more effort.

I honestly prefer zip or AppImage. Distribution independent, and it's super easy to get auto updating in Electron.

Since an AppImage is just a compressed filesystem, you can also extract its content very similar to a zip file. But you then will miss out on the easy binary delta updates using AppImageUpdate, and have an extra step of unpacking, and will need more storage space.

Seeing this in debian stable would convince me it's likely to be around in ten years (with security updates for the dependencies).

Shorter term, an Ubuntu PPA wouldn't hurt. Other people have other opinions and litmus tests, of course.