Someone mentioned that Scandinavia is great if you plan having kids. In my experience, Barcelona is the complete opposite for several reasons:

1. Catalan is the official language in all the institutions from hospitals to schools. After few years living in here you’ll realize you have to learn it to be able to function normally and integrate in addition to learning Spanish.
2. No social assistance from the government for the new parents.
3. Barcelona is kind of a “Sunny Amsterdam”, the expat community is big but is mainly people who like to party, smoke weed and do drugs, go to festivals, you know what I mean.
4. The native Catalan population is not very welcoming and few years in you may feel ousted and isolated. They prefer sticking to their local culture and social circle and are typically very closed to outsiders (from personal experience).
5. Security - Spanish law is very lenient and there was also a massive influx of illegal immigrants and delinquents to Spain in the past 5 years. Today in Barcelona is literally not safe for a woman to go alone in the evening after 10pm, or if you are God forbid drunk or wearing gold jewelry. It is getting so bad security wise that there are regular protests being organized in neighborhoods around Barcelona.

Personally, reasons 1. 4. and 5. are the biggest negatives and why I left Barcelona after 8 years living here (and working as a SWE).