When comparing Flatpak vs AppImage, the Slant community recommends AppImage for most people. In the question“What are the best Linux package managers?” AppImage is ranked 9th while Flatpak is ranked 17th. The most important reason people chose AppImage is:
Leaves your system untouched.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Cross-distribution
You can install flatpak packages on any distro you want.
Pro Doesn't bog system down like snaps.
Plus it's not proprietary.
Pro fast
searching, installing and updating are faster than others in my experience
Pro Application sandboxing
All applications are limited to a set of predefined permissions, enhancing privacy and security.
Pro A well-written documentation
Pro Flexible runtime management
You can install a lot of runtimes for different apps, making applications a lot more compatible while still allowing some applications to share their runtimes.
Pro No integration into the system
Leaves your system untouched.
Pro Easy to use
Just execute the package to run the software.
Pro Easy deployment of software
It just works across different distros.
Cons
Con Bloated
Due to the way Flatpack handles packaging, this can lead to a large cache being created which quickly inflates to unreasonable sizes. Not only this, but using flatpack requires a large chunk of space to be reserved for it's own file hierarchy.
Con No wayland support
Apps look pretty bad on 4k monitors.
Con No automatic updates
You have to re-download the application to update it.
Con Big file size
