The interview process was expectedly more tedious than most, but is not as bad as many claim it to be in terms of transparency, efficiency, and feedback, at least for my particular case. Aside from a non-functional archaic PDF employment application that wasn't compatible with Adobe (how ironic) and some constant probing of timeframes and interview logistics on my part, the experience was quite acceptable. I mean give em' a break, they are hiring hundreds of people a month...
First round interviews were conducted at my university's career center after I applied through online recruiting. It consisted of two back-to-back behavioral interviews with individuals from the Adwords team. Great experience, as I came prepared (read two or three books on Adwords and Online advertising). There was one quick mini-case question that Google likes to throw out every once in a while, but there is no right answer and it was actually a very reasonable one. I got called back the next day for a second round interview (very speedy).
Getting all the information and logistics ready for the second round interview was another story. After receiving the e-mail notifying me of my second round interview (no date, no time, no other information), I was in the dark for about three weeks. I repeatedly sent e-mails to the recruiters and finally got the logistics together. Hotels kept changing, but you do get a generous room service allowance!
The second round interviews were on-site. Shuttle picked us up from the hotel. You get placed with a group of other applicants (for the same or different position). They probably have one of these group interview days about every week. Spent nearly half a day there, doing the usual Google tour, meeting with some recruiters, asking questions ect. The interview was again another 2 back to back behavioral interviews with a couple of mini-cases about internet market sizing, how would you sell Adwords, ect. Again, nothing too out of the ordinary if you did you homework and can demonstrate a clear thinking process. Ate lunch at one of the gazillion cafeterias, had some small parting gifts, and off we went. Nice and smart people, but it seemed like the engineers definitely ran the show at Google.
Here is where the curveball was thrown. I was informed a week or two later that they thought I was more fit for another position (also within Adwords) and asked if I was still interested. Of course I agreed and we proceeded to reset the process all over again. Couple of weeks after another phone interview, I was given given the offer.
Overall it was an acceptable experience. The fact that it was with Google probably helped in keeping me excited and raising my patience level.