Not the most interesting city and certainly not worth an overnight stay. Generally far cheaper than Spain and Italy but food (except excellent fruit), and culture reflect the country's position as one of the poorer European areas.
A modern European city-in many ways the real capital of Spain. It is crowded and virtually nothing can be seen in a one day visit. Queues for the Sagreda Famillia, Picasso museum,Palau Catalana de Musica, etc are hundreds of people long. A hop on/hop off city bus tour is probably the best way of getting an overview. Flamenco and classical concerts start too late to attend if the ship is not overnighting. External viewing of Gaudi's architechture and the whole "moderniste" movement will either confirm your views- genius or lunatic-there is no room for indifference. Like Lisbon,Paris and Rome the city is infested with pickpockets and constant vigilance is essential.