When comparing ChromeOS Flex vs MX Linux, the Slant community recommends MX Linux for most people. In the question“What are the best Linux distributions for an old machine?” MX Linux is ranked 2nd while ChromeOS Flex is ranked 39th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Lightweight and fast
This is basically just Chrome OS which already runs on Cheap chrome books. It works well for web browsing and file storage on low end computers.
Pro You can try it via bootable USB
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 Limited hardware support
There is a list online of about 100 or so computers that officially support Cloud Ready, but it can also work on a laptop not on that list, results may vary.
Con Only really meant for web browsing
To use the software, you need to have a Google account and log in. Because it's meant for web browsing and researching, you won't find software like Steam, Office, Adobe Photoshop, Aftereffects, etc; or even a 3rd party browser other than Google Chrome.
Although there are plenty of alternative web browser online, and in the Chrome Web Store, which is still supported by Chrome OS.
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.