My wife booked a cruise for us on the Nieuw Amsterdam as a 50th birthday present. Round trip from Venice with stops in Korcula, Croatia; Istanbul, Turkey; Mykonos, Greece; Santorini, Greece; Kusadasi (Ephesus), Turkey; Katakalon (Olympia), Greece. We were scheduled to stop in Athens, but there was a port strike in effect so we had to skip it... instead we had more time in Istanbul.
Really had a fantastic time with very few issues. Having been on a few different ships now and a few different lines, I would have to say Holland America is a top notch line. The entertainment was fantastic even if geared toward the older set... top level singing and dancing and a great magician. one night featured just the men entertainers singing in harmony which was standing-ovation worth. My wife also enjoyed listening to acoustic guitar in the Crow's Next Bar and the piano player in the Piano Bar.
The food was consistently very good quality and a few times excellent. We booked reservations at two of the specialty restaurants and really enjoyed both evenings. The only exception was the pizza in the aft pool area... the pizza is kept under warming lamps outside and wasn't as warm or fresh as it could have been had the pizza been kept inside... just nitpicking here though.
Just a few tips - most of the passengers were over 60 so if you really want to hoof it and see the sights I would skip the HAL shore excursions. My wife and I really enjoy the challenge of getting around our destinations on public transportation so this was no problem for us. With a bit of planning you can see more and save money. In Istanbul the line offered a shuttle back and forth from the Grand Bazaar for $30, the last shuttle returning at 6 pm. There is a great public tram only a few blocks from the ship you can take to multiple destinations for only 4 TL round trip, and it runs through the night if night life is your fancy. Same situation in Katakalon (Olympia). Also, make sure your shore excursion isn't cancelled even if they give you tickets. We had tickets for sea kayaking in Korcula and it was cancelled, but they neglected to tell us.. this made us late getting ashore because we had to then get in the back of the line for tenders.
Embarkation and disembarkation went very smoothly. The ship was extremely clean and well laid out. The HAL employees were very friendly and service oriented... our cabin was always well tended to.
The travel guide gave some good presentations that weren't overly geared toward selling excursions and pumping up the HAL recommended souvenir shops.
Other notes: Bingo was $25 a card so we didn't play. The coffee bar was excellent. Internet service was good with many computers available. The hot tubs weren't hot enough for us, but then again, given the age of the passengers, this probably avoided a few heart attacks. Open dining was very enjoyable... we could get a table for 2 with very little wait and a table of 4 or more immediately.
Ride the donkeys up the cliff in Santorini - a highlight of the trip. :-)