[NathanKP]

1) It's probably a function of specialization. VLC is better at video because that is all they do. Windows and Mac OS X built in solutions are mediocre because they are part of a larger platform which isn't so specific. Also to be frank VLC is still relevant because it can be used to do things of dubious legality such as ripping copy protected DVD's and saving them in other formats.

2) A project which isn't getting updated to work on new platforms and with new API's is a dead project that fades from relevance very quickly. VLC is obviously looking ahead and has judged the Metro interface to be something worth investing in to maintain relevance.