I was also hesitating between Valencia and Barcelona. I ended up choosing Barcelona because there would be more job opportunities for my SO who doesn't work remotely.
Valencia is much cheaper than Barcelona but doesn't have a big airport nor as many good restaurants.
As for the best and worst things, I think they're valid for both Barcelona and Valencia:
The best thing is actually a combination of many: excellent weather conditions, relatively cheap cost of life, great food, access to the beach, overall good quality of life.
The worst things are the noise (cars and people) and communication.
Valencia is much cheaper than Barcelona but doesn't have a big airport nor as many good restaurants.
As for the best and worst things, I think they're valid for both Barcelona and Valencia:
The best thing is actually a combination of many: excellent weather conditions, relatively cheap cost of life, great food, access to the beach, overall good quality of life.
The worst things are the noise (cars and people) and communication.