we have done the package several times with both Hollywood & Vine and also Mama Melrose. We thought H & V was OK, but we really like Mama Melrose (although service is very slow.) On the regular dining plan, you get an appetizer, entree, dessert and beverage when you get the Fantasmic dining package which is nice since you don't usually get an appetizer with the regular plan.
Since they no longer do Fantasmic every night the package is very definitely worth it unless you want to get there 2 or more hours ahead of show time...even during very slow times of year the place fills up. We were there in September 2009...resorts were 1/2 empty, and parks were really empty...no waits on most rides and even the headliners like Soarin' and TSM had only 20 minute waits...but Fantasmic was packed. When they only do 2 shows a week, and they also close the other parks early, then everyone goes to Fantasmic the nights it's on. We were very glad to have reserved seats we could walk in and sit down 45 minutes before the show.
They do open up the F! seating to the public at about 20-30 minutes before showtime, so make sure you get to your seats at least 45 minutes before the show.