I have been meaning to reply to this for days now, but not had the time.
I have been in La Coruña NW Spain for 8 years now, been out of the UK for 15.
Generally things depend on what your circumstances are. If you need to earn money then obviously you have to go where you can work, or set up a successful business. If it's to retire you have to think about healthcare and mobility, and also things to keep you occupied - you cannot sit on the beach all day every day.
As regards to the location, I reckon that the place will choose you. I had no intention to live in Spain, let alone a far flung corner like La Coruña but I was sent here for reasons to do with work and fell in love with the place and made some very good friendships here. If you truly want to live somewhere then you can generally put up with the hard bits ... there are many.
Good things for ME about being in LA CORUÃ'A
I get to live where I want to.
I have learned a foreign language.
I am more relaxed than before.
I love my city.
I love the food.
The scenery is fantastic.
Galician people are similar to Brits.
It's not hot here and it rains aswell.
It's not cold either.
Being a city, there are bars, pubs, restaurants, cinemas, theatres, sports etc, etc.
The healthcare system works.
There is a reasonable public transport network - buses from where I live to the city centre every 15 minutes until 11PM (If I need them)
Beach only five minutes walking distance from the flat.
Spectacular, empty beaches less than 40 minutes in the car.
Bad things about being in La Coruña.
To Spanish people I will always be an immigrant.
Having to learn Spanish from scratch.
Jobs are hard to find, pay rubbish, are unstable and have long hours.
Beurocracy.
Civic pride is not what it is at home.
Whilst the family is very important here, community spirit isn't.
The television is rubbish.
Education system is not as good as the UK.