I had to reply to this as soon as I saw you were torn with the decision to leave Galicia--I used to teach there last year! I also wasn't sure if I should stay there or leave (though to try another region of Spain) because I too fell in love with it. After much agonizing, I decided to move to San Sebastian so I could experience another side of Spanish culture. Though I don't regret my decision (I've had some incredible experiences here, met wonderful people, and have a much better school), I don't think I would have regretted staying in Galicia either. I was just there for Semana Santa and was reminded of how magical it is. Now that I am off to Russia on a Fulbright, I am a little daunted by the idea of starting over in a third place in three years (but obviously more excited than nervous!). And I speak more Russian than Basque or Galician
Basically, I don't think either decision will be bad. If you go to Andorra, you'll be with a better, more organized program. You'll have a completely new cultural experience and you'll probably pick up some Catalan. But if you stay in Galicia, you'll deepen your ties there and build on your experiences from this year. I think it just comes down to if you want breadth or depth of experience. Good luck with your decision and congrats on having two great options!