These days when a disc labeled "2-Disc Special Edition" comes out, it can be hard to tell if it will be worth the extra money, since more often than not the extra disc only contains the film on Digital Copy.
That is the case with Valkyrie, however the features that are included are pretty decent.
The highlight is a 40 minute history documentary about the events the film is based on, and I can say it was very interesting to watch.
As for the other features, there was a 15 minute making of featurette with was fairly average and there are two commentaries.
All and all, this set world be worth it for the documentary, however casual viewers may want to just opt for the single disc set.