I don't think you can't compare the Nautica with the Navigator. They are not comparable. You would want to compare Voyager since the ship's are more similar - more alternate restaurants, activities.
Our next cruie will probably be a Baltic. Comparing O's Baltic, with Voyager's Baltic in July 08.
Regent: Cat H on Voyager
Fare $5795 (Special)
Air - not include
# of Days = 7
Per diem $827.85
Oceania Insignia: PH 3
Fare $6499
Air Included
# of Days 14
Itinerary inlcudes Kiel Canal transit, Brussells and Amsterdam. Overnights in ports.
Per Diem - alloing $1000 for air 392.78 per night
Tips and bar for us $50.00 pp per day $450. per day