Pros
You probably don't want to have to type the full path for every command you want to use. Add the directory containing your new GNU executables to your path in Windows. There are two root directories of executables to add: one for MinGW (including GCC and its related toolchain) and another for MSYS (including Bash and many common tools from the GNU and BSD projects).
Cons
There's much more to MinGW than what I can cover here. After all, MinGW opens a whole world of open source and potential for custom code, so take advantage of it. For a wider world of open source, you can also give Linux a try. You'll be amazed at what's possible when all limits are removed. But in the meantime, give MinGW a try and enjoy the freedom of the GNU.