Basically it seems like the applications fight over who will be the actual default application. If SMPlayer is installed and I select it as default, it refuses to let me choose VLC or Totem. I mean, I can select it, it looks fine, but if I close/reopen it's back to SMPlayer. If I apt-get remove smplayer and do the same things, this time Totem is the one who's continually set as default even if I select VLC as default. But fortunately as least the Nautilus way (properties - open with) works without issue.