[threesongs]

It is an important paper. However, it is also important to realise that superluminal solutions introduced there are still prohibited by the laws of physics. Making such superluminal drives is at least as hard as making superluminal matter, which we believe requires infinite amount of energy. In physics, they say that such spacetimes violate the dominant energy condition. The issue is relatively clearly stated in E.Lentz's paper accepted in the journal, but not in his arxiv paper or the press-release.