We are Americans who have visited the UK many times, and have been to all four of the component kingdoms. However, we wanted to visit the out of the way, difficult to reach places that not even most Brits have been to.
I had never heard of CMV nor the Marco Polo, but surfing on line for the itinerary that I was looking for, I found the "Around Britain" cruise that met my criteria. The port calls were Invergordon, Stornaway, Tobermory, Dublin, The Scillies, Guernsey, and Honfluer.
I also discovered that CMV is attempting to attract more American and Canadian passengers, and has opened a sales office in Florida to deal with them. We booked the Around Britain cruise departing July 26 with them. We paid entirely in US dollars and all went smoothly.
The Marco Polo is old but very well maintained. It was clean and attractive. Our category 8 cabin was spacious and had two port holes. Service was good, though in the fomal dining room the servers were spread too thin. The food was acceptable and geared to British tastes, which meant to Texans accustomed to barbeque and TexMex, it seemed bland.
The shore excursions were well run and worth the price. I especially emnjoyed the ones on Lewis. Mull, and Iona. Being partly of Scottish descent, my DNA seemed to be sayin "you are home"!
Some prior posters have complained about the behaviour of their "fellow Brits". Out of some 800 passengers, all but 26 were UK passport holders. The rest were Americans , Canadians, Australians, and New Zealanders. We found nothing but courtesy, politeness, and friendliness from the British passengers. We quickly became friends with our British table mates and are still in contact witlh them.
Almost all ocean going cruises have formal nights, and the Marco Polo is no exception. For men, they also prescribed sports jackets for most other nights. I complied, but as the cruise went on, fewer and fewer did. In this age of luggage limits on planes and outrageous charges for transporting clothing of limited use is no longer viable. I think all cruise lines need to rethink this and relax to something like " golf course" rules.
So, overall good marks. For my fellow "foreigners" reading this, give the Marco Polo a try.