I was a little disappointed by the article in this regard. While it's mentioned that "There is a small portion of the population — he estimates it at around 5 percent or even less — who, for what researchers think may be genetic reasons, can maintain their performance with five or fewer hours of sleep. (There is also a small percentage who require 9 or 10 hours.)" it would be very interesting to know if there is a larger than 5% group that does just fine with 6 or 7 hours of sleep.

Assuming your assumption about the distribution of "needing x hours of sleep to do well" is correct and if we assume that 5% need only 5 hours or less and the mean is at 8 hours (the article is even unclear about what those 8 hours represent so it's a wild guess at best), how large is the percentage of people needing 7.5 hours or less? (Roughly 40% if it's a normal distribution). So what the article says about "most of us" is technically correct the interesting answers for the many of us that presumably need between 5 and 8 hours of sleep is left out.

Does it make a difference in what sleep phase people are woken up (after the n hours of sleep their group gets)? I wish more money would be available for this area of research so longer and more detailed studies could be done. And better handouts for journalists.