There's only a narrow window in your life where many of the cons of working for a startup don't ruin you. That window happens to overlap with the beginning of your career. If you have the skill to make it into a big corp at the beginning of your career, you can do it again later in your career -- they'll still be there later.

I'm of the opinion that the generalist skill set you typically get from a startup is far more valuable than the specialist (and typically exclusive to the corp) skill set you get from the corp, and I'll even argue that the entry level skill set of the corp is pretty damn useless, but that's only from anecdotal evidence.

What doesn't kill you makes you stronger, startups dance at the edge of survival.