Wait a second, though. Team dynamics are a key factor of any startup's success (as snprbob was just saying at http://news.ycombinator.com/item?id=2208326 ). Difficult people screw that up.
So "sometimes we make money with brilliant people who are easy to get along with, most often we make money with brilliant people who are hard to get along with" may well be an accurate description of Sequoia's results, but the most likely explanation for it is that it's due to how they're selecting during their funding process and then how they're interacting with the companies once they've funded them.
Someone can be difficult from an investor's perspective, but not so with a team member. Both a team member have different personalities and motivations which might not align. Co-founders are probably more likely to have found an alignment, then moved forward together.
Also, if co-founders are friends, they've likely learned to get over each one another's difficult spots and manage to have a bond that lets them work together.
So "sometimes we make money with brilliant people who are easy to get along with, most often we make money with brilliant people who are hard to get along with" may well be an accurate description of Sequoia's results, but the most likely explanation for it is that it's due to how they're selecting during their funding process and then how they're interacting with the companies once they've funded them.