In terms of the difficulty, what you find online gives you a pretty good idea of what you will need to do to prepare. I found that the process was incredibly slow until I had other offers on the table. After telling them about the other offers it was sped up a little, but mostly I was just being strung along. I first spoke to a recruiter, was given an automated coding test, then after I passed I was connected with a different recruiter. The recruiter asked a few questions, then set up two harder coding interviews where I was matched with two different Google engineers and asked to "whiteboard" on a shared google doc. I've been told after those two, normally there is a third before the application packet is sent to the first hiring committee. I, however, only wound up doing those two interviews. After the hiring committee, you are sent to "host matching" where you wait in limbo for a while. Your packet is in the bottom of the pile when you are first sent to host matching, so it's very likely you will be waiting for a few weeks before your recruiter contacts you to interview for a team. After a few interviews, you rank your preferences and they do the same. If you get a match, your packet gets sent to another hiring committee and if you pass, some VP reviews it and signs your contract. They claim to not care about grades, but they really do.