Finland - September in Lapland - Rovaniemi/Pyhä or Ivalo/Saariselkä?

Planning a few days in Lapland next September 11-14. Which of the two of these (or open to others) would y'all pick? Will be coming from Helsinki and then going on to Bergen. Would love to experience ruska and the northern lights (hopefully), like small quieter towns more than bigger bustling cities. I'm a total noob on this part of Europe so please feel free to shoot me straight! Open to all suggestions.