New
#11
Essentially I think.
VLC supports a very wide range of codecs and the containers (sort of files) that the codec data lives in. It supports VOB, ISO, MKV. VOBs will have mpeg2 coded video plus a range of audio codec support.
The version of Windows media player I have doesn't support much that VLC does.
So to answer your original question. There's nothing wrong with Windows media player if you like the user interface and it's A/V support. I don't.