I was solicited by an in-house recruiter. Whole process very smooth, went through phone interviews, a code challenge, then onsite in SF with 5 rounds. They seemed well-prepared and I was happy that they took the time to send me a detailed schedule of the onsite with a list of who I would be meeting with in each time slot as well as how long each meeting was expected to be. I had another offer on the table and they graciously sped up the offer and decision process and was able to get back to me in just 2 days.
In general HR/recruiting was super responsive and quite helpful, although I found it a bit strange that they don't really provide their phone numbers only email - when I needed to get in contact with them I had trouble finding any numbers despite all the email correspondence we had, but luckily one HR person had called me before so I was able to trace the number back through caller ID. Overall a great, professional process. Left a good impression on me.