I guess it depends on whether or not you want to spend the money for the new "extras" that are included. The quote below points out what those extras are:
The new material includes 5 featurettes totaling nearly 75 minutes in all (Godfather World, The Masterpiece That Almost Wasn't, When the Shooting Stopped, Emulsional Rescue: Revealing The Godfather and The Godfather on the Red Carpet), 4 short films (Godfather vs. Godfather Part II, Cannoli, Riffing on the Riffing and Clemenza) and a hidden Easter egg.
