Took first cruise on the Holland America line and was generall very pleased. Food was excellent, service in the main dining room was very good, ship was clean, deck chairs were readily available, pool warm, entertainment excellent and lectures by Brett and Microsoft workshops by Molly great. Having a daily Catholic mass on board was a plus. I did not try the spa,bingo, gym or art auctions. There is a great deal on laundry but no self-service machines. You can put all you can in a bag for $20! We had so much in it that I wondered how they got it out!
However, the shops on board were way overpriced and the service in the Italian (reservations needed but no extra charge) restaurant was awful. It left us wondering if this is where the line trains their waiters. Salads were forgotten one night and bread another. Wine had to be ordered three times one night and two the other. That said, the worst rip off was the internet - slow and expensive. In Aruba there is a very cheap internet cafe right on the dock at the terminal. Wait and walk around town and do it later when there are no lines. I think it was $6 for 90 minutes! The ship charged $50 for less time.
In terms of side trips: the travel through the whole Panama Canal was expensive ($149) but worth it if you have never done it.