voip vs tdm fallout

Is it too soon to start to compare and contrast how voip held up vs. tdm? Back in the old days circa mid to late 90's, there was a lot of hand wringing about whether voip would be up to the task of dealing with a massive emergency. Well, we certainly have one now in Japan on almost every front imaginable. Is voice such a small fraction of data that the larger issues of cuts, electricity, etc make it moot, or has there been some appreciable differences between the two's ability to stay in usable service? Mike