I have only done Disney in the Med. My sister did Princess for British Isles. Any future sailings to Europe (and parts of the Caribbean) will be open to any number of companies.
I watch a lot of cruise videos and have seen there are so many options out there - some for significantly less than
DCL.
When it’s time to venture out, I see it as a research and discovery adventure just to decide; I would even consider those not marketed to US/Canadian cruisers.
First is an honest look at what cruise vibe / environment you enjoy. Quieter or more party. I view cruise food as subjective and just okay - with highlights in most lines (I have sailed at least once on Carnival, MSC, Royal, NCL, and Princess - that the most, mainly Alaska. And mainly Disney).
My take on cruise lines, summarized from my experience and/or reviews by many vloggers -
Holland America - music as entertainment, less crowd pumping parties. Lower passenger capacity, even their largest ships.
Princess - similarity of ships across the fleet. Not big on bells and whistles (slides, go karts…). Light snacks in (large, high) atrium 24h is a + Movies Under the Stars is similar to FunnelVision. The Princess Air program has a good reputation.
Royal Caribbean - seems to focus on large ships with lots of active activities. Specialty dining in lieu of utilizing included meals means a higher price than you see listed. Beds are often described as uncomfortable. Ships often have a shopping mall promenade instead of Atrium. They often utilize their older / smaller ships to interesting itineraries - with a vibe more similar to Princess.
Carnival - The FUN ships. They will pump the crowd - even during dinner, when the waiters dance (yes, Disney parades its servers, but not to the same extent). They are building bigger and add-on activities as they sell off older ships. I liken them to a tail-gate party.
NCL - known as the cruise without all the rules - eat when you want, dress as you like for dinner. They seem to be having problems right now settling into what they are offering - or eliminating. Also has a lot of specialty dining for a fee. Their Free at Sea ongoing offer does provide a decent package for dining, drinks, and internet. Recent reports on their Air program has families spread across different flights and little or no ability to have any input or change to air reservations.
MSC - new guy in US, Italian-owned and -minded. Lower prices but reviews seem to include the phrase “for what you paid.” If the itinerary is great, especially port intensive, it might be a good option.
I find workers on cruise ships to be generally hard-working and friendly. The level of interaction does vary - but it does not play a significant role in my vacation, unless I run into a serious problem that gets dropped (in reality, I can’t recall anything after the cruise).
Look at where you actually want to go - which I assume is the reason for flying across the Pond - more so than the cruise line. And times in port.
If you want to see the Norwegian Fjords - changes are coming in a few years to restrict visits to ships meeting tighter emission limits to the UNESCO World Heritage areas (I think this affects two main destinations).
What I am looking forward to eventually (fingers crossed): Fred Olsen in the British Isles to include Orkneys (Kirkwall), Hebrides (Stornaway) - both for stones like Stonehenge. P&O for Norwegian Fjords. Also, NCL from Tampa for port-intensive Southern Caribbean. (We did one on Disney and realized we didn’t need Disney prices or entertainment for a “beach vacation.” And beds split on NCL - like most cruise lines). Would like to try HAL; considered it for AK, but port hours are often late arrival. Will most likely do a 4th Princess AK cruise - went there with DCL first).
