Google

It was long, and after two phone interviews, I was scheduled for an in-person one. They totally messed up on that last part. I was first contacted by a recruiter, and I informed them about the progress of my career. They said Google would be certain

I had two recruiters during the process. Both were nice, and the interviewers were generally pleasant. Consider it a collaborative effort to solve interesting problems. I went through almost every stage, but somehow did not get the final VP's bless

The process was a bit slow, but overall, both the recruiter and interviewers were professional and nice. The questions were also very practical. There were five rounds of interviews over two days, covering programming, algorithms, and system design.