Do you want to do a consumer startup or an enterprise startup? That's the obvious dividing line between them. FaceBook will prepare you to do a consumer web startup, because that's what they are, 6 years down the line. Palantir will prepare you to do an enterprise startup, because that's what they are, 6 years down the line.
Ignore everyone who says that FaceBook will look better on a resume: that's only true if you work outside of the valley, and you don't want to start a tech startup outside of the valley. Among people who matter (investors and key early engineers), Palantir's reputation is at least as good as FaceBook's.
Smaller company doesn't necessarily mean you'd learn more. Interns learn a shit ton at Google, with its 25,000 employees, and I think you'd learn a lot at both FaceBook and Palantir. The important variable here is how flat and open the internal culture of the company is. There are startups where you have 10 people but the CEO never tells you a damn thing, and then there's Google where you have 25k people but full-timers can access just about everything (and even interns have pretty broad access and get exposed to a wide variety of technologies).
Really, I think the biggest decision is consumer vs. enterprise, and I don't think you're equipped to make that until you've worked for both (that's what internships are for :-)). Personally, my first job out of college was a startup that sold enterprise software very similar to Palantir's to hedge funds. I hated it - I wanted nothing to do with the financial industry, I found the enterprise sales cycle to be capricious and demoralizing, and I didn't like the feeling that we were beholden to a few very powerful and questionably moral customers. I wanted to do consumer stuff, and I'm much, much happier now that I'm at a consumer company. But I have friends that have gone the other way: they felt that consumer stuff was frivolous and mundane, and liked the algorithmic challenges of building industrial-strength software for very wealthy enterprises.
Ignore everyone who says that FaceBook will look better on a resume: that's only true if you work outside of the valley, and you don't want to start a tech startup outside of the valley. Among people who matter (investors and key early engineers), Palantir's reputation is at least as good as FaceBook's.
Smaller company doesn't necessarily mean you'd learn more. Interns learn a shit ton at Google, with its 25,000 employees, and I think you'd learn a lot at both FaceBook and Palantir. The important variable here is how flat and open the internal culture of the company is. There are startups where you have 10 people but the CEO never tells you a damn thing, and then there's Google where you have 25k people but full-timers can access just about everything (and even interns have pretty broad access and get exposed to a wide variety of technologies).
Really, I think the biggest decision is consumer vs. enterprise, and I don't think you're equipped to make that until you've worked for both (that's what internships are for :-)). Personally, my first job out of college was a startup that sold enterprise software very similar to Palantir's to hedge funds. I hated it - I wanted nothing to do with the financial industry, I found the enterprise sales cycle to be capricious and demoralizing, and I didn't like the feeling that we were beholden to a few very powerful and questionably moral customers. I wanted to do consumer stuff, and I'm much, much happier now that I'm at a consumer company. But I have friends that have gone the other way: they felt that consumer stuff was frivolous and mundane, and liked the algorithmic challenges of building industrial-strength software for very wealthy enterprises.