The main difficulty, apart from moving away from friends and family, is the need to learn a foreign language. As far as I know, the Spanish education system doesn’t actively encourage such learning, in parts of the province I live in they are still forced to learn a ‘dead’ language, Valenciano. Just a bit further north, it’s Catalan. Neither will help them if they move abroad.
And the closer your family life, the more difficult it becomes to leave them behind.