The whole process is exhausting. But not tough questions. Only thing I realized after I joined in the company is that some persons do not know many things, but interview gives them a chance to ask you. They the targets or knowledge they get from you become theirs. So you are thinking they are interviewing you with questions, the fact is that they try to get something from you. Now I know they do this to everybody.

Interview is standard. Full day with 1 h seminar and 30 min meetings with stuff. Negative impression. I traveled from different state to their interview. The company promised to reimburse ground transportation from and to airport and never did. Just ignored my emails after the interview. This is not a question of money, it is a question of a company's culture and respect to candidates.