Naples offers a great choice of excursions: history, culture, scenery. That's why it scores highly. As for the city itself, it's busy & noisy, as you might expect, although we took no risks & felt safe enough. We strolled from the ship to the national museum, a very easy 30 minutes. This is well worth it, but is not available on any excursion. We came back via the square where the old Royal Palace is, which is wide, & well supplied with itinerant African traders offering several varieties of junk on their rapidly portable stalls & blankets. There are a number of attractive buildings near the dock.
Not much to see here. Busier & dirtier than Naples. We took the little road train for 8 euros each, but the way it's designed means that you don't really get to see much above first floor level. There was nothing that we whizzed past during the 50 minute ride that we felt deserved a second look, anyway. The city didn't tempt us to walk around.
It was mostly shut on Good Friday, so we didn't see it to advantage. We walked up La Rambla, which is really just a big market, & turned back when we reached Sagrada Familia, where the queue was round the block. In a back street we had a beautiful glass of wine at a bodega where we were not made to feel especially welcome. Despite that, we'd go back to Barcelona because there's a lot left to see. The city centre is about a mile from the ship.
The most pleasant surprise of the cruise, for us. We expected an industrial city, but at the pretty Vieux Port there are a string of pavement restaurants where you can watch the world. They don't want you just to sip a drink, though. The tourist road train (7 euros) is well worth taking, going along the coast & up to the basilica, which is beautiful inside, & offers panoramic views of the city & the sea. The road train lets you off there, so can take some time to appreciate it. The coach from ship to town was 15 euros each, but if you walked about a mile you could get a local bus for under 2 euros. It would not be sensible to try & walk all the way in.
Nobody we spoke to who had gone off the ship had enjoyed themselves much. Carthage offers little that's memorable, & in the souk you get harrassed to buy stuff that won't enhance your life.