When comparing Slax vs MX Linux, the Slant community recommends MX Linux for most people. In the question“What are the best Linux distributions for desktops?” MX Linux is ranked 13th while Slax is ranked 54th.
Specs
Ranked in these QuestionsQuestion Ranking
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 Easy to use
Pro Supports non-free drivers
Pro MX Snapshot: lets you make your own distro
Can create your own ISO (snapshot) and use it either as live-session and install back when needed.
With the (pre-installed) Snapshot tool you can easily create an ISO of your running system and then save it to a USB (or other media) and use "your own" distro as a live session or install back whenever you like (even on a different PC with different specs with no issues). You can even give that customized ISO to friends (selecting "non-personal" ISO when creating the snapshot; thus resetting the accounts & passwords and Home folder etc.).
Also you can save that ISO directly encrypted via MX Live USB Maker tool. Again, you can install MX encrypted during installation with just ticking a box, no matter if it's the official ISO or your snapshot.
Pro Good MX Tools and Package Installer
MX Linux comes with its own set of tools called MX Tools, designed to make life easier for users.
Pro Easy install
Pro Based on Debian
It is based on Debian and not based on Ubuntu.
Pro Lightweight
Pro Very stable
Pro No systemd
Pro Can also be used as an emergency tool
It has almost all tools to repair non booting systems or recover files & folders and save them on a safe place. And when thought together with it starts quick on live-session. In addition, you can do these with "your own", customized distro (snapshot).
Pro Live-Session boots fastest after Puppy
After Puppy Linux (which's aimed to run from RAM and which is smaller in size) the second fastest (head & shoulders) booting one (together with the sister project antiX) and also has the option "toram" to run from RAM. Yes, not only when compared to full distros, even far faster than small sized or tiny distros, especially when booted to "live-session", about 2 - 2.5 times faster on an old single core laptop.
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 Only one Desktop Environment
Con Its XFCE version is too laggy
XFCE is meant to be lightweight, and it's almost true for other XFCE distros but not for MX Linux.
Con Old software
Many software applications are older.
Con Remixed Debian testing
It's mainly a Debian stable with some recompiled/backported Debian testing packages.
Con Includes non-free drivers
Con More than 50 tweaking softwares pre-installed
Con Longer boot time
Con 10s of media players preinstalled
Con Too much preinstalled applications
Con Causes overheating on some hardwares
Other debian based XFCE distros- Xubuntu, Debian XFCE, Devuan leave small footprint on system whereas MXLinux uses too much CPU resources on same system.
Con Installer and configuration tools are different
Installer and configuration tools are different and can take some time getting used to.
Con Too much customization
