After some time working in "start-ups" this is one thing I agree with more than anything. "Hours While people occasionally choose to push themselves to work some extra hours at times when something big is going out the door, for the most part working overtime for extended periods indicates a fundamental failure in planning or communication. If this happens at Valve, it’s a sign that something needs to be reevaluated…
I've also heard that the everything-is-flat model isn't all that great either. Yes you get to work on what you want, but, going back to the stack-ranking, it can be quite the political place if you want to get on the right projects, etc.
I'm not trying to say that Valve isn't a great place to work, but I think people romanticize it a little too much when this handbook gets trotted out on HN every other month.