I did okay in my interview with google but was passed over. The truth is they are always interviewing, so I think being hired has more to do with the timeframe of your interview than anything else. It's very similar to how the military drops many "requirements" of a soldier when what they need are bodies.

At some points, google is spinning something up, and at those points they need more devs, so they hire more of the interviewees. I think the rest of the process is basically random, based on the gut feelings of an entire team of random people.