1: "will I get the chance to work on technology that I really want to work on?"
2: "will I get mentoring from great senior developers?"
I advise them to spend the first five years of their career honing their skills in the craft of software development, I advise them to pay no attention to money - I say "it will come later if you have become a great software engineer".
Interestingly, I feel alot more is to be learned from working at a disorganised and chaotic company, at least in the early stages of your career. When you later see things done right then you'll truly understand why things are done in the way they are, because you know how it can be done badly. Which is to say, it doesn't matter if the company you work at is well run or not.
It always makes me feel that a junior developer is off track if their primary selection criteria is anything but the opportunity to learn how to become a great developer.
I guess maybe its different in Silicon Valley.