This is considered the "birthday" restaurant in my family, especially for Mom. With a setting like the Central Park Lake right at your feet while you dine, this is hard to beat for ambiance. You are transported somewhere other than being right in the middle of Manhattan, a rare experience for diners in the city.
The food here is also very good; very rarely have I come across a "miss" while dining here. They are very big on fish and steak, which for the most part are well-prepared and delicious. The staff is always hospitable and the attire goes anywhere from casual in the restaurant to black-tie for the countless weddings they host here.
In addition, there's an outdoor bar with tables abutting the Lake, on the side of the restaurant itself. This makes for a great afternoon just sipping drinks, while watching people row the boats which are rented out by the hour. The only downside is getting to and back from the restaurant, if you're not already in the park, especially at night. The staff, however, do what they can to get that unpredictable Boathouse Shuttle to arrive, so that you are safely escorted out of the park.