I have done the 7 night NCL, the 11 night one way Ensenada to Honolulu on Celebrity and have done 15 night roundtrip on Celebrity once and Royal caribbean once. And without a doubt for us the 15 nighter is the most cost effective and pleasant. You spend 4 days sailing over, a week in the islands and sail 4 days back. We never got jet lag, Hawaii is 5 hour difference from our time zone, and we got cheap roundtrip air to San Diego. The food is wonderful as well as the service and cabins. I cannot say that about NCL. It often times is CHEAP but there is a reason for that, people talk and most of it is as bad as you have read. I cruise a lot and I would never do NCL Hawaii again, no matter how low the price is. My feeling with Carnival, if you are going to spend 12 days on the cruise and you still have to get one way air from Hawaii and dollar for dollar, it will be up there is price, even more than the 15 nighter. I booked in April 2006 for the 15 night sailing October 2007 and for a balcony we are paying only 1570.00 per person including port charges and tax.