We did the 15 day Baltic cruise from Stockholm to Southampton. The itinerary was great and the shore excursions excellent. We choose not to take the long bus/train rides into Berlin, Paris or Brussels but instead enjoyed exploring the smaller cities near the ports.
The Norwegian Spirit is in need of refurbishing but we didn't spend much time on it. The food was mediocre but adequate. Unfortunately the dining availability did not match the excursions and sail away times. We came back late from excursions twice to find only a very small cafe open to get any food at all.
Another issue was that the ship docked in many industrial port areas away from the nearest cities. There were cruise ships docked much closer to the ports but it seemed that we always were docked much farther away requiring shuttles and such.