If you can afford it, the seats in Business class are much better. Depends on the airline, of course. British Airways has greatly improved their seats, and the food in the business class lounge at Heathrow 5 is amazing. Practically a full Indian buffet!
Air France's lounges are not as good, but their on board service is, and their seats are good, too. Avoid American (the nationality, not the specific carrier) airlines, as their planes, comfort and service are inferior to the European carriers. And I say this as one who often takes Delta from the States back here, since the only nonstop from the Southern USA (except Florida) to Düsseldorf is the Delta flight out of Atlanta.
I only took a long distance ship once, back in the sixties, from New York to Le Havre and, a year later, back. It was an old converted WWII era converted Italian freighter. It used to cater to students studying abroad. I heard it burned completely several years ago. I learned how to say "don't throw up here!" in Italian and how to pronounce "sjösjuk (seasick)" in Swedish. I was miserable the whole time.
I just get seasick, no way around it. I have had some hairy near-misses with planes (take German Wings between Düsseldorf and Barcelona all the time, e.g.), but I would have gladly traded seven days of agony for a quick demise while I was on that boat.
Price hint on business class travel, by the way: from here (Europe), at least, you can take advantage of passenger poaching wars for a good deal on business class fares if you know where to look. Lufthansa and Air France, for example, fight each other tooth and nail for transatlantic passengers. Lufthansa offers sometimes over a 50% discount of the Air France business class fare if you fly from France to the USA via Frankfurt. Similarly, Air France offers a huge discount over the Lufthansa business class fare to the USA and back if you fly from Germany via Paris. I'm talking like the difference between 4500 euros and 1700 euros!! So, since I'm in Germany, I always fly Air France/KLM and change in Paris or Amsterdam. Delta is part of the Sky Team, so I can get an Air France code-share flight number and book the Delta flight for the trip home, although the word seems to be out, and it's getting harder and harder to get a cheap seat on that flight. It IS awful taking a transatlantic flight, arriving someplace exhausted (you lose the night) early in the morning, and then having to go through immigration, a terminal change and security again, but if you are coming from the States, you get to land at your destination at the end of the longest trip, and that is always best.
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