Phone interview is about basic/text book machine learn knowledge that you can learn from classes. Couple of easy questions about using unix command line. On site interview is to meet with four different people in the team. They try to get a sense of your experience in modeling, big data tools etc and how I would apply those to their products. The overall experience was not as challenge as I would expect as a top company would offer. People at management level don't seem to ask the right level of questions or they just do not care that much. Recruiters are not the most professional ones when dealing with candidates. These are signs for the company culture that you could probably imagine.

I found the position from linkedin and applied immediately. Recruiter replied on the same day and scheduled a tech phone interview next Monday. Phone interviews asked algorithm and math questions. Recruiter replied same day again and arrange Friday onsite. Onsite interviews including 4 team members (Sr data scientist & VP data science, two data scientists). They are very talent and welcome. Questions covered different aspects. The whole interview process is very systematic and logically start from easy to harder.