Crossing longitudes by ship, cruise or otherwise, is a great way to minimize the effects of jet lag.

As for the QM2; from what I've read, the basic hull design of the QM2 and the Queen Victoria is shared with various Carnival Corp ships including HAL's Nieuw Amsterdam and Eurodam, Carnival Spirit class and various Costa ships. Not sure I buy the fact it is an ocean liner. Maybe more power than a cruise ship of the same size (HAL did that with 4 ships which are near identical: 2 of which are designated for global voyages and thus have 4 20 cylinder diesels while the other two not designated for such have 16 cylinder engines instead (and thus lowered max cruise speed by 2-3 knots).