MoreAK

Something that we did as it was important to me was: count the number of sea days, count the number of port days, count the number of different ports.  Viking has many ports with 2-3 days overnight and not so many different ports.  Princess was cheaper but had a LOT more sea days and less ports.  HAL was the right mix and length for us.  Of course, itinerary rules everything.  Another thing that I highly recommend since you are planning so far in advance - take a two week cruise on that line, preferably the same ship used for World, and make sure that you really could stand to be on that ship for 100+ days.  It is easy to use any of the multi-line, online travel sites, such as *****, to compare various itineraries.

As a 5-star Mariner, but first time World Cruiser on WC2020, I heard (from other passengers when we were bobbing in the pool) that HAL was THRILLED that over 400 passengers were first time World Cruisers on WC2020. They were also pretty happy that the expensive, Over Land/Over Night, excursions sold out very quickly, probably due to new passengers.