The interview process was in order;
* a introduction with a recruiter,
* a thirty minute introduction with a head of the department
* a hour our technical interview of Rust questions, and a leet code problem
* a two hour interview of one hour cultural fit, and then one hour of pair programming on Rust problems
* a two hour onsite of one hour architectural white boarding, one hour technical discussion on my history, and a 20 minute meet and greet.
In all it ended up taking about 8 to 9 hours (some parts overran, and that includes travelling time). I believe I had completed all rounds. I was not made an offer.
Positives:
It was a challenging interview process. You would need a few years of Rust experience to pass their tests as they test a wide variety of knowledge. All of the interviewers were very talented, and were both friendly and respectful throughout the process. Some actually taught me some things (which is a huge positive).
Negatives:
Programming challenges are done on the Leet code editor, which is a very limited IDE. I lost time battling this and getting less done. One example is the errors only show up in a tiny 3 line box, and only at the end of the session did I find out you could expand this to make it easier to read.
Some of the interviewers are in other parts of the world making interview times a challenge. On one interview I had to get up at 6am.
I rated this a negative because after spending almost 9 hours, across 5 interviews, and making it to the end. They didn't provide any reason for the rejection, and no feedback (I did ask). For me that soured the whole process and would discourage me from applying again.