My husband and I will be on that cruise. There are quite a few posts on a Cruise Critic Board (Google cruisecritic.com, go to "Boards" and look for the Sun 4/27/04 cruise site). No one has been on the Sun, but one of the people posting and going on this cruise did a similar cruise last year from San Francisco to Vancouver.
What kind of trouble have you been having with NCL. Our experience so far has been excellent, but we used a TA.