Difference between MinGW and the regular GCC?

On the SourceForge page for MinGW, you can download the GCC 4.5.2 and that's the latest version. On the GNU mirrors, you can download the GCC 4.6 source and compile it with one of the possible windows targets:

i[3456789]86-w64-mingw*
i[3456789]86-*-mingw*
x86_64-*-mingw*

Is there a difference between using one of these targets and the traditional GCC for MinGW? Would it make sense to use the regular GCC because it has more up-to-date versions or would it make more sense to wait until an up-to-date GCC for MinGW is released?