When comparing Virtual Box vs Flatpak, the Slant community recommends Virtual Box for most people. In the question“What are the best FLOSS Sandboxing Apps for Security/Privacy and Daily Usage, Linux?” Virtual Box is ranked 3rd while Flatpak is ranked 4th. The most important reason people chose Virtual Box is:
It works for Windows, macOS, Linux, BSD, and many others.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Compatible with Many Operating Systems
It works for Windows, macOS, Linux, BSD, and many others.
Pro Beginner friendly
A virtual machine can be set up in minutes if a ISO file to load is already available.
Pro Works well and fast for Windows host and Linux guest
Pro Free and open source
Pro Many free images available
Though most are linux flavors at https://virtualboxes.org/
Oracle's virtualbox site has others.
Pro Can do snapshots
Pro A lot of customization
VirtualBox has multiple virtualization options. Each one may be tailored to the guest operating system’s needs. This makes it especially good on virtualizing older systems, such as DOS, obscure distros, etc.
Pro Cross-distribution
You can install flatpak packages on any distro you want.
Pro fast
searching, installing and updating are faster than others in my experience
Pro Doesn't bog system down like snaps.
Plus it's not proprietary.
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.
Cons
Con Lacks video performance
Virtualbox has a hard cap of 256MB of video memory. This could make newer operating systems run slower.
Con Minimal CPU customization
You can only enable/disable certain features. You cannot cap the speed of the CPU, which is required to run systems such as Windows 95.
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 Difficult to export packages
It is difficult and convoluted to export installed packages and move to another system.
Con Doesn't work well with CLI programs
Invoking CLI programs can be a pain. From the weird reverse DNS package names to difficulty in easily managing container environment.
