When comparing Slax vs Linux From Scratch, the Slant community recommends Slax for most people. In the question“What are the best Linux distributions for desktops?” Slax is ranked 54th while Linux From Scratch is ranked 63rd. 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 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.
Pro Best for learning the components, libraries and configurations of the whole system one-by-one
It is an opportunity for the learner to learn what's behind every piece of program in the system, because you will install and configure all the packages manually. It is also as an advantage to expand your knowledge by searching the possibilities of crafting your unique flavor, for example your own package manager and update schemes.
Pro For those who wonder what it takes to create an actual Linux distribution
It's a very useful learning experience; showing the user what is required and in what order, to obtain a running Linux system - from the inside out.
Cons
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.
Con Not recommended for Beginners
By creating a Linux system from scratch you will be managing and compiling all of the systems packages by hand, so advanced Linux knowledge is recommended.
Con Takes a while to create the system. Only for those people who would like to create their very own distribution, or just to understand what makes a Linux system tick.
Linux From Scratch, requires the user to download and compile, all the various required system libraries and programs in a ch-rooted environment. This is usually done from within an existing and already running Linux system. This is not really a con, just a note to the new user.
