Cinnarch stands for Cinnamon and Arch, so basically is a Cinnamon Desktop based on Archlinux from Spain, that does fairly okay; not very popular, not completely unknown.
Alexandre Filgueira explains the reasons for the transition from Cinnamon to GNOME Desktop:
Today (April, 10), we’ve made the difficult decision to change the direction of our distro.
While Cinnamon is a great user interface and we’ve had a lot of fun implementing it, it’s become too much a burden to maintain/update going forward. We’d like to remain faithful and compatible to our parent distro, Arch Linux, and further support of Cinnamon would strain that by causing incompatibilities/hacks in the entirety of the Gnome packageset. It is almost impossible to maintain software developed by Linux Mint in a rolling release as we are. They’re 1 year behind with upstream code. Arch Linux is going to have soon Gnome 3.8 and Cinnamon is not compatible with it. The Cinnamon team still have to migrate some of their tools to fully work with Gnome 3.6.
That said, we’ve decided that in order to deliver the most stable, best out-of-the-box user experience possible, that we’ll now be using Gnome as our default desktop environment going forward. We know this decision may upset some of our loyal users, but truly feel it is the best path forward for long term support/maintainability.
In light of this decision, keeping the name Cinnarch could seem misleading. So, we are asking the community what do you think about changing our name. Should we change it or keep Cinnarch?
You can answer our poll in our forum post, here
We still have the same great team behind us, so are confident that we can work through this to create a truly great, easy to use Gnome based distro!
We’d like to thank everyone for their support so far, and like to promise you an exciting new Gnome release coming up soon. We are also hoping to hear your favorite gnome extensions, configuration options, etc. for consideration of being preconfigured for you in our next release.
Also, thinking about the future, we’re gonna give the user the choice of selecting his favourite Desktop Environment while installing.
Please, if you have any productive comments, suggestions, or feedback regarding our transition, please contact us at email@example.com or post in our forums.
Yesterday was the last day that Cinnarch released with that name. They are now looking for a new name that will identify their new GNOME Desktop.
There is also a recent interview (Jan 20) of Alexandre in Linux Updates.
Good luck to them!