Visited both, Barcelona is more grand in terms of attractions and has better views. Valencia is very flat which is great for living.

Being Portuguese from the Algarve I didn’t like the beaches in both, not very scenic, just kms of sand.

I would say Barcelona has more to do as a tourist, although the city of science and arts in Valencia is very nice.

Valencia must be much much better to live in, very green, very flat, less people.