When comparing FireJail vs Virtual Box, the Slant community recommends FireJail for most people. In the question“What are the best FLOSS Sandboxing Apps for Security/Privacy and Daily Usage, Linux?” FireJail is ranked 2nd while Virtual Box is ranked 3rd.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Advanced sandboxing
Pro No problem running graphical programs
Games and video-accelerated programs have no problems running in the jail.
Pro Very flexible with little overhead
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.
Cons
Con Hard to use
Not very easy to set up, may require terminal usage.
Con Primarily command-line driven
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.