Is mingw still active?
Solution
Well, this is probably a very personal topic, and here's my very tainted view on things:
I provided a GCC 4.6/4.7/4.8 build for mingw-w64 (see link below). I do so because they provide both a 64-bit and 32-bit capable CRT, which mingw.org (the old one) does not, and is not planning to.
Mingw.org development seems quite halted, although they still provide updates, I'm not clear what these are (quite frankly I don't follow them either). MinGW-w64 has support for DirectX, DDK, and the *_s APIs, among other things, which the old mingw.org still does not have (or at least not as complete).
Note the two compilers are not sworn to binary compatibility, so you'll need everything compiled by one vendor's toolchain (either mingw-w64 or mingw.org).
There are packages available for various Linux distributions, and Windows users can use the installer, MSYS2 (which comes with a package manager and a huge amount of prebuilt packages), TDM-GCC, and Nuwen's MinGW distro which includes the Boost libraries.
OTHER TIPS
I see < 14 hours ago
on the Modified time for MinGW-w64, so it looks pretty active to me...
(They're actually 32-bit, btw.)