First, let me start by saying that you should not fly Iberia to get to Barcelona. I flew from Dulles/Madrid/Barcelona, and I am still waiting for my luggage 72 hours later; unfortunately, I found out to my dismay, after the cruise, that Iberia loses 17 pieces of luggage for every 1000 passengers.
Now, onto the cruise. We embarked in Barcelona, 2 passengers in our 30s, with little trouble. Prior to embarkation, we did have to wait for the pre-arranged NCL bus that waited nearly 45 minutes to fill before we could leave from the airport. If we were to do it again, we would take a cab from and to the port; it would have been around the same price (if not cheaper), and easier than waiting for buses to fill up.
Upon arriving at the port, embarkation took only 20 minutes until we were on the ship. Luggage, however, arrived much later to our room, with NCL replying that they had til 7:00PM to deliver it.