I felt like there was tremendous variability in the interviewers. Some were disinterested, some were engaging. Some asked relevant questions, some clearly had no idea what my background was or what position I was interviewing for. Some asked canned questions and wanted canned responses. Some explored my experience and knowledge with open-ended questions.
It is my experience that interviewers from countries with rote-learning based educational systems ask canned questions and expect regurgitated answers. Interviewers from western educational systems performed more fluid interviews(where, incidentally, I excelled).
I do not believe Google's current interview process selects for the type of smart people they claim to want. Then again, they're now a big, not-so-benevolent corporation with lots of grunt work(i.e. maintenance, bug fixing) so maybe they just want effective robots?
I'm fully able to admit that I just wasn't smart enough for their organization. Then again, another leading tech company loved me and stuck me on their core design team. Based on my conversations with Google's engineers during the on-site, I did not feel like I was dealing with the best and brightest, whereas at my new company I felt awed by the depth, experience and accomplishments of the team.