I have a lot of complaints about some people at YC (specifically those who say a lot of stuff about people in private—or even worse, on bookface—that they don't say in public, and engage in other childish cowardly behavior), and for all I know SamA has said sh*t about me behind my back (but I don't have any evidence he has ever done so nor do I suspect it), but in all of my interactions with him, he has been generous with his time and helped me figure out some key decisions (like when I was deciding whether to sell to Microsoft in 2014, he did office hours with me and helped me figure it out).
He's also put out a ton of honest, insightful, unique content out there that I've learned a lot from.
I think PG did him no favors by basically saying he was the Lebron James of startups when he was like 20 years old or something, but surprisingly he did live up to the hype.
Definitely someone who is able to see the forest from the trees and identify where the key roots are and act accordingly.