I worked in their US Fleet for a few years. Very laid back, quirky crew, fun–mostly young people. 3rds will have very little watchstanding time for a number of reasons–mostly because they drive zodiacs full of passengers around all day. You will definitely see some amazing sights, eat delicious food, and meet some great people. For the right recent academy grad it’s an awesome job for a few hitches as long as you don’t mind the 180/day and–last I heard–uneven rotations (2/1 months). Still, probably the most fun you’ll have in a “shipping job.”
The new ships suffer from some shortsighted design issues and missed opportunities for a new “expedition” build.
The US Fleet works SE Alaska in the summer and, depending on the boat, Baja or Panama/Belize/Costa Rica in the winter. The International fleet is a whole 'nother thing. They don’t hire US officers.