A few disclaimers - I am 23 years old and American, so some of my thoughts are colored by the perspectives of age and nationality!
Embarkation and Disembarkation: Embarkation, as most people have said, was very smooth. My parents and I arrived in Copenhagen the morning of sailing and spent a few hours around the city. We took a public bus to the port and everything was a breeze from there! We went had lunch in the Seven Seas main dining room, took a self-guided tour around the ship, and found our luggage waiting for us when we were ready for it.
As for disembarking, we docked at around 5:00 a.m. and as my parents and I had a 9:00 a.m. flight, we didn't want to chance it and decided to try to get off the ship as soon as possible. We were able to do this without problem - we just had breakfast in the garden cafe and walked off the ship with our bags straight into a taxi. The taxi from the port cost about 73 USD.
The ship: The last time I went on a cruise I was 10 and was not paying attention, but now that I am old enough to appreciate things properly, I have to say I thought the ship was lovely and the perfect size for the journey that we took. There are 2 main dining rooms, the four seasons and the seven seas, though my parents and I preferred the seven seas because there were more water-view seats and it was larger, making it feel less crowded. It took me about a day to get the hang of the ship, though it took my poor old parents a few days longer! We were in a room on the 10th deck near the forward part of the ship, 1 floor below the spa and fitness center, and I found it quite convenient to elevators even though I mostly took the stairs. Everything is well maintained if a little dated and occasionally the public restrooms get a little...well, you know, from time to time. The stardust lounge reminded me of Vegas, but I liked that it was a little cheesy, as well as the casino, the galleria shops, and the main atrium. It's a beautiful ship, if one of the smaller in Norwegian's fleet.
Also, I have to add a note in here about the high quality of the fitness center, being a bit of a workout junkie myself. The fitness center is amazing, and there are 2 personal trainers who work there and run a few complimentary and a few paid classes. Try them out! It'll make you feel less guilty about hitting the buffet and the personal attention you'll get (let's face it, how many people on a cruise really go to the fitness center?) is really worth being there. My mom tried out the spa and enjoyed the experience even if it was a bit pricey.
The cabin: We had an inside stateroom, which slept the 3 of us comfortably with a sofa bed for me and a queen for my parents. The bathroom, while small, has the best water pressure I've ever experienced - while travelling or even in my own home! I will miss that a lot. Decor was nice and the room was generally quite comfy.
The food: A lot of people complain about cruise food, but I have few complaints actually, despite being a bit of a foodie. We did not try any of the speciality restaurants, and ate most of our dinners in the seven seas and a few in the four seasons. However, I did hear great things about Ginza, the sushi restaurant for a $15 cover charge. The food quality in the main dining rooms for dinner was an 8.5/10, and the best meal I had in the dining rooms (they have the same menu as each other every night) was an English cut strip sirloin with yorkshire pudding, and a close second was broiled salmon with pasta that is on the "always available" menu for the less adventurous. Going backwards, the lunch menu in the main dining rooms is the same every day, but there is actually a good variety if you are willing to try something different each day - my favorite was the salmon and shrimp salad sandwich with sweet potato chips. The breakfast menu also stays the same, but if you're smart enough to try the smoked salmon eggs benedict, you will not regret it. It was probably the best thing I put in my mouth during the whole vacation.
As far as the buffet goes, my parents took an Alaska cruise on the Norwegian Star and my mom went on for hours about how large and well stocked the buffet was, so I had high expectations and was a little disappointed that Sun's buffet is not that big and closes periodically throughout the day and at 9:30 p.m. There was variety amongst the choices, but the only time I'd really recommend the buffet is for breakfast, which was really good. Also, don't miss the handmade crepes during dinner time at the sprinkles ice cream bar!
Only big food complaint - the chocolate buffet! I am a huge chocoholic, and it was the biggest disappointment of the cruise. Nothing aside from the chocolate covered bananas tasted that great, and I was so sad that I had to waste 75% of my plate because I just couldn't stomach it :(
The entertainment: I thought the entertainment was pretty good considering all the slightly negative reviews I read. Our cruise director, Pedro, did a good job of hiring talent that did not alienate the many different nationalities of people on board, though most of the entertainment was geared towards English-speakers. If you're lucky enough to have the crazeehorse acrobats or sander and alison (magicians) perform on your cruise, don't miss them! The NCL produced entertainment was not as good as the hired entertainment, but it was still pretty good.
See my port reviews for more info about the 6 wonderful cities we visited!
Anyway, about Berlin. As soon as we got off the ship, we were met by an SPB tours bus driver who took us to the city (3 hour drive) to meet our guide, a delightful American ex-pat named Preston. It was pouring rain and freezing cold and yet we had an amazing day and so much fun seeing the city! I know a lot of people want to stay in Warnemunde, which I heard good things about and actually might have wanted to do if the weather was better. However, going into Berlin is really worth it - it was the most interesting city we saw! SPB tours takes you to all the important places - checkpoint Charlie, the reichstag parliament building, the main church in the city, the Olympic Stadium, etc. Wherever our bus parked, we also saw the NCL tour bus parked and felt good that we paid a lot less to see the same things ;)