I participated in an onsite interview loop for product manager. The interviews were in Mountain View. I had 4 interviews back to back (1 software eng manager, 3 PMs), then lunch with a PM, followed by 1 more interview (with PM) via Google Hangout after lunch. With 4 back to back interviews it was a bit exhausting so might be an idea to practice to get accustomed to it. The information on Glassdoor as well as the prep info from the recruiter gives an excellent idea of what to expect. There weren't much surprises for me, but the tech interview seems to vary a lot so I didn't know what to expect there. Each interviewer seemed to focus on a certain area, eg. tech, estimation, product design, etc. I spent most of the time in each interview tackling the main question, and then the interviewer followed up with a few behavioral type questions. I found the interviews to be fun yet challenging. It was a lot of talking and white boarding. Everybody was very respectful and helpful with hints if I went astray. Personalities of course were different with some being more friendly, but it was a pleasant experience with everyone. The recruiter was wonderful and responsive in answering questions and assisting in any way she could. One downside is the abundance of prep info and material out there makes it difficult to prioritize what to tackle. If you were to actually go there all of the material suggested by the recruiter you'd probably be prepping for months. I think the material is a good guide to calibrate where you're at and understand what would give you an edge if you already possess that knowledge/skill, rather than actual "training" material.

You would have to do a hiring assessment first, then a recruiter screening follows. First round interview with the hiring manager. Majorly product sense and product improvement. The questions were not direct though.