AppImage makes me nervous because they don't actually create promise cross distro compatibility—it depends on what libraries the developer decides to ship alongside the AppImage, and which they assume the distro has. This also raises questions about forwards compatibility with future OS releases.

Snap and Flatpak, by contrast, have explicit systems in place to prevent this. Of the two, I much prefer Flatpak for being a community-driven project. Also, Snap doesn't let you disable automatic updates (without hacks to your hosts file or such). Whatever you think about the security implications, this feels very against the Linux ethos of the user always retaining ultimate control.