Yes, pacman is wonderful. We're very grateful to the Arch Linux devs.
You guys are all correct, we've not paid nearly enough attention to marketing. Here's the description I tried to post:
MSYS2 is an updated, modern version of MSYS, both of which are Cygwin (POSIX compatibility layer) forks with the aim of better interoperability with native Windows software.
The name is a contraction of Minimal SYStem 2, and aims to provide support to facilitate using the bash shell, Autotools, revision control systems and the like for building native Windows applications using MinGW-w64 toolchains.
We wanted a package management system to provide easy installation of packages, and ported Arch Linux's pacman. This brings many powerful features such as dependency resolution and simple complete system upgrades, as well as providing the build system (makepkg) which is used to make these packages. The set of software-building recipes (PKGBUILDs) for MSYS2 itself are at:
mingw and MinGW-w64 are not the same thing, so that URL would be less than useful.
MSYS2 is firmly in the MinGW-w64 camp. The schism happened when GCC was ported to 64bit Windows and we've not looked back since (much; working together is always to be preferred but sometimes that is not possible).
We're investigating why sourceforge will not let me update our description.
I've installed it recently using info from: http://sourceforge.net/p/msys2/wiki/MSYS2%20installation/
It has a port of pacman (!) from Arch Linux for package managing. It feels so much better than mingw-get (package manager used for MSYS/MinGW).