I see the genius in this approach by the band, with the video, especially if it is Mangini. I hadn't liked a single video I've seen of him on Youtube and had they announced him as the drummer I'd have been disappointed to be sure. Now seeing him in action with the band at a relatively early stage, I'm convinced by him. He seems to have a love of the music and a determination and he comes across as likeable.
He does seem to have an advantage in already knowing everyone, as the pleasantries seem more effusive in his vid.
I loved what we saw of Lang and he's still my number one, just an awesome heavy hitting drummer, Minnemann as well is awesome, definately more progressive, but I see that DT would be safe with Mangini.
Consider me persuaded.