It is my understanding that P&O have recently made it easier for US guests to book, which is good. The current exchange rate will go in your favour and you will find the drinks cheap onboard, plus no extra tips on top as it’s all included. Leaving from Southampton it will be largely Brits onboard. Not sure about the older ships, but generally it will be slightly better dressed in the main dining room in the evening than our most recent (pre pandemic) Royal cruise, where anything went. It won’t have ice skating rinks or rock climbing walls and in December getting up early for sun beds won’t be an issue.