Sixty-eight deaths from around one thousand infections is a lethality of 7%. That alone should make us take this very seriously until we have more data.
Update: On San Luis Potosi (some 400Km north Mexico City, second biggest outbreak) has been reported 62 cases and 5 deaths, 8% http://bit.ly/15VOOt
So far, all confirmed cases in the US have been mild. And they probably caught it from others who got over it without triggering any alarm. So don't head for the hills based on early fatality extrapolations from Mexico just yet.