I saw "Slumdog Millionaire" and thought it was a good movie - I haven't said that about a movie for a long time. So I say it is worth your money. The theater was packed and no one made a sound, even during the credits; which you should watch.
It did use the "Usual Suspects" method of telling the story but that was good also.
I didn't see "Benjamin Button" but from the video below; I may have. Comparing the two I think it shows the problems with Hollywood - lack of imagination, repetition and the inability to tell a good story. This is another industry that will be losing out to imports like the auto industry.
The Curious Case of Forrest Gump from FGump44