When comparing GNU Guix vs Slax, the Slant community recommends Slax for most people. In the question“What are the best Linux distributions for desktops?” Slax is ranked 54th while GNU Guix is ranked 58th. The most important reason people chose Slax is:
Changes you make in the configuration persist if you run from USB.
Specs
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Pros
Pro Can setup a shell which has exactly the defined libraries available
A method which works across languages and provides a reproducible programming environment.
Pro Can always roll back to a safe state
Guix creates new profile generations for each operation. If anything goes wrong, a simple --roll-back gets you immediately back to the previous, working, generation. Because it is a purely functional package management system, generations don't affect each other, so you're back to the exact same state as before : still working.
Pro Can create independent packages
Guix pack creates packages which do not need Guix to be run.
Pro No side effects when building packages
Guix is a purely functional package management system. This means that the act of building a package does not have side effects, such as destructively updating or deleting files that may be used by other packages.
Pro Can build containers right-away, from docker to tarballs
See guix pack --help and here.
Pro Easy to add your own packages
The clean and declarative syntax makes it easy to define new packages by using an existing one as an example.
Pro Doesn't require root privileges
Normal users can install packages on a Guix-enabled system, or even run their own Guix instance if the system isn't Guix-enabled.
Pro Persistent changes
Changes you make in the configuration persist if you run from USB.
Pro Pretty fast to boot up
It was considerably fast to turn on when booting from cd.

Pro Modules
Standard tar archives plus some simple shell scripting produces modules that you can load dynamically into the OS for added apps and functionality.
Pro Modern desktop

Pro Small footprint
About 200mb, but with a full KDE4 environment and loads of useful apps.
Cons
Con Updates take a long time
It's gotten better over time but both updating Guix itself and updating the installed packages can take a long time.
Con Cannot handle filetypes that have different semantics across different versions
While the functional approach that Guix takes is great for sandboxing binary artifacts of packages, it seriously lacks any power in handling configuration files or user data. It's difficult to upgrade and downgrade files where semantics and syntax can change between versions.
Con Overly complicated HDD/SSD installation
While it has a nice layout Slax's lack of an installer tool like Tinycore's just can't be justified. It seems strange that it comes built in with programs that some users may not want, yet it doesn't have an easy way to install it. Due to its heavier use of RAM, built in software, and lack of an installer its hard to choose it over TC.
Con Works slowly on old computers
Con Infrequent releases
Since Slax is maintained by only one person, releases are not that frequent. So it may take a while to get bug fixes or new features once you start using it.
