In Outliers, Gladwell analyses the critical elements that go into making a successful person. He debunks the theory that perseverance and hard work makes success. While they are necessary attributes success, they are not the whole story.
Gladwell outlines that other factors contributing to the success of a person are circumstances of birth (most of Silicon Valley's tech lords were born between 1952 and 1958), and he has the 10,000 hour postulation. Anyone who wishes to succeed at any endeavour ends up putting at least 10,000 hours into the field that causes their success.
Gladwell is a highly readable writer, and each of his points is richly illustrated with interesting anecdotes backing them up. However with Blink!, his book on human thin-slicing, the book fails compared to Outliers, because it is all anecdote and very little meat and anatomy of thin-slicing. (Thin slicing is making snap judgements with very little concious information).
All in all though, Gladwell's books, and indeed his body of writing is pure brain candy and well worth consuming the useless sugar calories of his anecdotes that come with the sharp and clear writing of the phenomena that he chooses to write about. He deserves to be a best-selling author.