Cruiser sector investments be it by external companies or by the port, are contributing not only to the economic bliss of Catalan tourism but also to Spanish economy in general. According to a study from the European Cruise Council the cruise industry provided Spain with 1.190 billion euros in 2010.
To better understand about who runs what and where in the cruise terminals at Barcelona's port, I think you should check this official brochure entitled Barcelona Cruise Facilities 2013.
Regarding Barcelona cruises, I must say that there are many to choose from and it all depends on your budget, the cities you want to visit and of course the quality of the service. I would pick up of course a Barcelona to Barcelona cruise with the best quality-price relationship and a fantastic itinerary. I reckon it is not an easy task. Have you ever been on board of a cruise ship in the Mediterranean? Which cruise would you recommend?