Depends entirely on where your life is based. Whatever you do just don't sign up to cross the river ever day to work/hobbies etc!
As a blow in I find it is a generally very safe, friendly city and the schools tend to be all high quality.
Think about your budget, taste in houses (New build with 3 bathrooms? Tiny centuries old stone cottage? Renovator's dream?), preferences for schools (traditional Catholic? Gaelscoil? Educate Together? Steiner?), ability to commute (don't own a car and need to live in the city? Happy to drive in from Spiddal or Clarinbridge every day and back?) etc etc. Once you've narrowed that stuff down the possible locations will become a lot more obvious.