If you want something smaller, faster and tons more efficient for OS X, I highly recommend MPlayerX instead. It's everything VLC is, and more, with none of VLC's bloat.
I used to be a Perian user, but its complications and shortcomings made me ditch it in favor of MPlayer OS X Extended, which eventually led me to the better MPlayerX. I am in favor of Perian's solution of being a nifty QT plugin, though.
That means things will work fine in any app that uses the OS X APIs to render video.
Including QuickView .. really nice to be able to just hit space bar in the Finder to see a quick preview of a movie.