I was going to sort of make fun of Gladwell but chickened out. Grote broke the ice. Honestly, though, he's okay if you consider his origins as a magazine writer, whose job is to hype whatever he's writing about. He takes research and blows it up beyond what the actual researchers who came up with it would ever do.
I haven't read Outliers, and, although it's obvious the fact that success owes a lot to luck and circumstance, and then to hard work second, strikes me as being very, very worth saying, in a day where people believe we have a "meritocracy" contrary to all the evidence. (#1 predictor of how you'll turn out in life is how rich your parents are, not your own "merit." Also, there is less social mobility in the US and Britain than continental Europe. I've met plenty of smart people who think that we have a nation where smart, energetic poor people do better in life than dumb rich lazy people.)
If you like modern "secret hidden truth of whatever" authors, I'd recommend "Predictably Irrational" by Dan Ariely and everything Nassim Nicholas Taleb has written.