I had this delivered to work and have been itching to get home and see if these would work on my European Blu-Ray player. After checking into things i was convinced i was going to have to buy an American Blu-Ray player and explain to the wife why i had wasted so much money.
However, i can fully promise that these are region free. Each one worked straight away (Iron Man and the Hulk downloaded some extra content from somewhere called BD direct through my internet connected player).
As I do not have a 3d player/TV i cannot vouch for the 3d discs of Thor, Captain America or the Avengers. But each of the 6 films and the initiative disc all got to the first scene of the film (then i stopped it to eject and try the next one).
Decent value for money, looks amazing. I am definitely the coolest person i know.