After eight years here my experience is the same as pondgirls except we do go to Amposta often and everything she said applies there too. My partner who speaks no Catalan or Castillian but understands some has encountered one rude and unhelpful person in her nearly five years here. As for being understood I have had no problems in Barcelona or down south although everyone knows I am English and learned to speak the language in Tarragona due to my accents. However I have met expats complaining bitterly about the rudeness and unhelpfulness of certain people who I have found to be sweetness and light and willing to try very hard to help me.
Bruixot