As this will unfortunately be a review of our rather poor experience with Holland America, I'll start out with the things I think they did well.
I really loved the decor, especially the amount of comfortable seating to be found in the common areas of the ship. Being a social person, it's nice to be able to sit and people watch or read a book in a fabulously stylish yet comfortable chair. It's the little things in life, I suppose.
In the same vein, the Explorers Lounge at the front of the ship was one of if not THE best common areas I have seen on any ships I've sailed with before. First off... it was HUGE, with lots and lots of windows and a ton of comfortable seating both for groups and for people sitting on their own. It had the largest selection of books, puzzles and games (they even had Apples to Apples!) I've seen on a ship. The coffee bar was very small, but they did have some fantastic looking sandwiches and treats.