I think Spain is the best country to live in Europe if you have income/business in other country. I have been living in Marbella, Las Palmas de Gran Canaria and Valencia. Both Valencia and Barcelona are big cities and I compare living in the city and not the metro area.
Weather and Pollution. The weather in Valencia is a little bit milder, but for me there is not big difference.
Parks. This is why I like Valencia the most. It has 9km long park Turia located in the old bank of the river. Apart from that I like the Cabecera park (next to Bioparc zoo), Jardin de Vivers (collection of roses and kids playground to learn traffic signs) and finally the new Parc Central next to Ruzzafa. The city of Barcelona really lacks parks and greenery.
Barcelona here is real winner. 4x more startups funded in 2021 compared to Valencia. Trade shows and fairs. Meetups and conferences = probably 10x difference. Barcelona startup district.
Both cities have great international schools. Read about Valencia schools here and Barcelona schools here.
My favourite neighborhood Padralbes – 6800 euros per square meter (2022 June). Sarria – Sant Gervasi – 5800 euros per square meter. The most expensive El Pla de Remei in Valencia – 3900 euros per square meter.
Barcelona is a clear winner here, where it has more than 6x bigger airport by passenger count.
If your priority is family life – choose Valencia. If your priority choose Barcelona.
** with 0,5M income Barcelona can be good with family too.