I have one booked for May and still on the fence.
NCL has a system whereby you can bid on auction for an upgrade up to two levels. They can be fairly cheap. That will probably change. They might even let you go higher.
If I were going on a cruise, that’s the line I would take. They are nice.
most of the ‘upgrades’ are just location, unless you can jump to jr. suite or suite. Might be worth it to get a “superior” that is a little bigger also