Google flew me out to California after a single phone screen. I and my phone interviewer had gotten along very well; we covered tech, management, and process in about 45 minutes.
The recruiters were nice, although "nice" in a generic sense - you got the idea that they saw thousands of candidates each week and you were not even a name to them (for example, my recruiter had not remembered that I was unwilling to relocate, and was applying for Google in my city). The recruiting coordinators, though, were absolutely top-notch. I had a minor emergency that required a last minute reschedule, and they pulled heroics to get me there on time. Kudos to you RCs.
The interviews themselves were a mixed bag. Google was using the Microsoft-style interview process (and, oh, how they would hate to see themselves compared to the hated MS!) where you get an as-appropriate "as-app" interview at the end. So you don't know exactly how many interviews you'll get. If you get walked out in the middle of the day because your later interviewers "went home" or were "suddenly pulled away on an emergency" then it's already gg.
My first interviewer was amazing - the caliber of Smart Person we all like to work with. We had a great conversation that precisely split between business and tech. Incredibly good to talk with, although I didn't do well (this was apparently the mobile group, and I cannot possibly express how little I care about mobile - I don't even use apps).
The second interviewer, by contrast, was someone I would have fired from my org. He wasted his time and mine by asking me a stupid puzzle question - something about weighing gold coins - which I figured out quickly. Puzzle questions like this are stupid. They teach the interviewer nothing about how the candidate will function in their job; if they know the *trick*, they'll pass. Sure, I figured it out, but it was a complete waste of time. I've done well over a thousand technical interviews in my time, and I would have disallowed this.
Most of the rest of the interviews - basic service design, lunch-and-culture-fit, scenario-based problem solving, and technical conversations were all reasonable and fine. My final interviewer (the "as-app") did not want to hire me from the word go, however. He started late, cut early, and spent the intervening time checking his watch. I've had bad interviews before - as I said earlier, my first interview here didn't go well and it was entirely my fault - but this guy had ZERO interest in interviewing me. I would have been happier if they'd just cut me early.