AppImage is my first choice because each image includes absolutely everything you need to run a program with no pre-installed infrastructure.
Snap is my second choice. With Canonical behind it, it has a lot of really sophisticated functionality. Ubuntu Core can only run snaps, and snaps maintained by Canonical get a green check mark.
Many Gnome apps are available as Flatpaks.
That said, I don't like using any of these when packaged by an unknown party 🙃
@kai I'm with you on AppImages. If it's not in the existing PPA, but an AppImage is available, I have no problems using that. It just works.
@donblanco I understand the appeal of snapd. It's very powerful. There are a lot of features.
Flatpak seems like the worst of all worlds. You still need to have a daemon installed because some libraries *are* shared (and isn't the whole point of this to avoid that?), and as a result you get some amount of file size reduction. You also get a certain amount of containerization.
@kai I found snaps to be very hit or miss, and I ended up installing all of them in --classic mode which kind of violates the point of them in the first place...