Thumbs up - Copenhagen is an easy city see on foot. Parts of the old town are lovely. Lots of shopping, good restaurants, and people are friendly. The subway/train/metro system is clean. Recommend doing a canal/waterway cruise, Tivoli Gardens.
Be on the lookout - Their currency is the Kroner. While they take some dollars and some Euros (paper only), your chance will come back in Kroners. Also, use of credit cards in the stores require inputting a PIN number. Make sure you take a card that has a PIN number associated with it.
Thumbs down - Copenhagen is EXPENSIVE. Norwegian put us up in the Crowne Plaza Hotel. It is removed from the city. There is a mall across the street for shopping but it wasn't open (Saturday/Sunday) while we were there. The Crown Plaza has beautiful rooms and is clean, BUT the staff is TERRIBLE, slow to respond, and is a skeleton crew for such a large hotel. Stay somewhere in town so you can walk around and enjoy the city.
If you are a walker, Helsinki is an easy city to walk. If you're a non-walker, it's best to take a bus tour. The ship is docked away from the city, so you will need to find a ride into the city. Hop-on/Hop-off site seeing buses were at the port for 30 Euros. We took a taxi into the city for 10 Euros total (4 of us in the taxi).
Stick your head inside the Kampe Hotel...very old and nicely restored. If you can have a drink at the Savoy restaurant, order a Marski and have the staff tell you the history of the drink in wartime while you overlook the city.
If you don't go into the city, there is a great souvenir shop outside the area where the ship is docked.
The Berlin excursion gets 5 stars! There was a 2.3-3hr train ride to and from Berlin. Once in Berlin, we rode a bus throughout East and West Germany to see the city. We saw a lot of the city and the top 10 highlights.
Upside - Photo ops at sections of the Berlin wall promoting freedom and unity are powerful. Checkpoint Charlie was interesting to see. I'm glad we took this tour to stop and get out of the bus to take pictures and get a better view of the sites. Walkers and non-walkers could handle this tour, although it is a long day.
Downside - The stop for lunch featuring a "traditional" German meal gets 2 out of 5 stars. The wait staff was great but the food was not. German buffet with Spam actually being one of the meats served. The "German beer" served was cold (not traditionally German) and tasted like Miller Lite. I love German food and this was pretty lame. This restaurant was used to herd tour groups and didn't have any locals.
If you want authentic German beer, save your Euros for the train ride back to the port.
The second day we took the all day "Magnificent St. Petersburg" tour. It was a day well spent. We got to see a lot of interesting things and soak up the the feel of Russia. Catherine's palace was great and it was a good experience to get out of the city and see a little more than St. Petersburg. It would've been great if we had time to get to go inside the Church of the Spilled Blood but there was not time for that.
Recommendation - Skip "Russia Through the Eyes of the People" and take the palace/gardens/Church of the Spilled Blood tours instead.
While Stockholm is a big city, the Old Town area is easy to on foot. The main "shopping street" is not much more than souvenir shops and a few restaurants. Walk around a few of the Old Town blocks to see some different sides of Stockholm. Definitely go see the palace and the changing of the guard. It is unlike any you will see.
For non-walkers, take the bus tour around the city. You will actually accomplish more.
Stockholm uses Kronars...not like Dutch Kroners. While they take only Euro bills, you get change back in their money which can't be spent anywhere else. Stick with credit cards that have PIN numbers if you can.
There was a lot of confusion at 3:00pm when NCL passengers had to congregate on the sidewalk to get buses back to Nynaeshmn to the cruise ship. Site seeing buses have "cruise ship" signs on them too, and I think some passengers got confused and got on the wrong bus.
The day we were there, the village center had a little market in the afternoon which was quaint.
Upside - Beautiful, quaint village. Three Sisters restaurant offers and incredible, low cost lunch! Lots of handmade, high quality goods. They are known for their amber in this region and the prices were good. I probably did more souvenir shopping in Tallinn than any other city.
Downside - None, if you're a walker. If you are a non-walker, the little hills and cobblestones may be a challenge. NCL offers a half-day bus tour and then half-day walking...the walkers in our group wished they hadn't spent their morning on the bus.
If you skip Tallinn, you can shop in the little tents just outside the port where the ship is docked.