I support whatever the people want. If I were to vote, however, I would probably be in favor of continued union with Spain because it is the path of least resistance. If Catalonia were to become independent, they would lose membership in the European Union which would cause a whole host of problems and Spain would likely veto any future Catalan EU application.
In the end, however, I am not as vehemently opposed to Catalan independence as I am Scottish independence. Even though Spain is now a democratic country, there is a long history of undemocratic regimes persecuting Catalans—something that never really happened with Scotland in the UK.