We did the priority seating with Tusker House in May 2009...and I feel it was WELL worth it. We did have the dining plan...but as long as you made your ressies between 1 and like 1:40 like PP said, you get a voucher/ticket for that 3 or 3:15 (can't remember exact time) Nemo show.
You do not really have to wait in the queue line much at all with this voucher...you go through a separate door on the right hand side of the theater...you are seated RIGHT UP FRONT on the right side of the inside of the theater. It is air conditioned in there, so a nice place to wait for the show to start.
It is an amazing production if you have not seen it. Truly unbelieveable!! One of my favorites at Disney. I can never decide if I want to watch the puppetry or the actual cast member's face!! It is SO great!!
We went in December of 2009 again...and did not do the priority seating lunch. We went to the theater maybe 45 minutes before the show started...we were like 4-5th in line. And once the doors opened to go inside, we got perfect seats.
If you have a packed day at AK, I would go for Tusker House and get the reserved seating...that way you don't have to waste time waiting in line. Tusker house has good food...very ecclectic mix...with some traditional foods as well. The interior of the restaurant is fun too...I loved just looking around at the design and architecture.
Let me know if you have any other questions...
ENJOY!!