I rented this DVD at the local library because Tom Cruise's Valkyrie wasn't available yet.
I think it's a good movie, well done by European standards.
Pros:
It's in German which is for me, as a Dutchman born after 1945, almost a second language. I heard Tom Cruise's film was in English throughout... bah!
Smoking was allowed in Germany around this time so everyone smokes and the whole set is covered with cigarette smoke.
It's solidly acted, apart from some wooden performances.
It gives a good account of the way things went wrong.
It's not a big budget film so there're no enormous explosions, sets etc. it's more or less intimate.
Germans can still play Nazis very very convincing.
Cons:
Although everyone can read about the story I didn't beforehand and the whole thing confused me a little. (At school I learned most of the first German Kaiser not WWII I think). Not one moment is explained what Operation Valkyrie in fact was.
There're many people involved with many small roles so it takes some time to get to know everybody.
The panic and confusion after the assassination and the way von Stauffenberg tries to get control of things is underplayed. Not very convincing. I've seen Sebastian Koch in das Leben der Anderen too (The Lives of Others) in which movie I found him more convincing.