When comparing Chromium OS vs Puppy Linux, the Slant community recommends Puppy Linux for most people. In the question“What are the best Linux distributions for desktops?” Puppy Linux is ranked 10th while Chromium OS is ranked 89th. The most important reason people chose Puppy Linux is:
Puppy Linux requires 128MB of RAM and 333Mhz of CPU, although 256MB of RAM is recommended.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Safe and requires little to no maintenant
Since you only have the browser, you cannot install applications (outside Chrome Apps which are decently protected by their limited API and the Chrome Web Store). This means no harmful virus, and also nearly no way you can screw your system. Everything will just work.
Pro Minimalistic interface
Chromium's system UI uses as little screen space as possible by combining apps and standard web pages into a minimal tab strip: While existing operating systems have web tabs and native applications in two separate strips, Chromium OS combines these, giving access to everything from one strip. The tab is the equivalent of a desktop application's title bar; the frame containing the tabs is a simple mechanism for managing sets of those applications and pages.
Pro Lightweight
Because Chromium OS is designed for users who spend most of their computer time on the Web, it is intended for use in computers with little local storage and fast boot-up times.
Pro Extremely low minimum system requirements
Puppy Linux requires 128MB of RAM and 333Mhz of CPU, although 256MB of RAM is recommended.
Pro The whole OS runs off of RAM
Since Puppy Linux is completely loaded and run off of RAM instead of HDD, it's read/write speed is not a factor.
Pro Designed to run as a live USB/CD
A portable version, that can be carried on a thumb drive without requiring installation, weighs less than 100MB; a Live CD - less than 150MB. You can even save your settings and files for Puppy on the external device/media.
Running off a live CD also has security benefits, as your system will reset to the known config after each boot.
Pro Different distro based versions available
Puppy Linux offers a few different releases.
The first is an Ubuntu based release called Tahrpup, by using this version the user is able to take advantage of all software and support from Ubuntu.
The second version is called Slacko, which is built upon the Slackware binaries.
The third is called Wary and it is built to support older hardware than the rest.
And the fourth is called Quirky, which is used as a base to explore new ideas.
Pro Linux distro designed for this exact purpose
Pro Offers a long term support release
Puppy Linux offers an LTS release called Precise.
Pro It can be the only distro that works
Sometimes, Puppy Linux is the only distro that works on an old machine: all other distros are more demanding.
Pro JWM used as window manager
JWM is a low resource window manager that is used in most Puppy Linux installs.
Cons
Con Google
Possibly harms your privacy.
Con Made for developers
ChromiumOS is mainly made for development, so there exist no official install images and you have to build it from source or use third party images like Arnold's or the waterfall images.
Con No auto-upgrade (unlike Chrome OS)
Chrome OS auto-upgrade the system, but Chromium OS does not. It's possible that they're thinking about adding that feature from the design doc.
Con A bit ugly
Using puppy makes you feel like you just jumped 20 years into the past. Being that the purpose of Puppy Linux is to run or really low resource machines the software used is often on the older side, which is precisely why it has a 20 year old look.

Con Not as light as it used to be
It's light, but not as light as it was 1-2 years ago.
Con Smallest software library ever
You can barely find any precompiled packages for Puppy.
Con No built in compositing
Being a low resource distro there is zero built in compositing for the JWM window manager. Though one can be added through a bit of work.
