I was hired by their on-campus recruiting, which began in September, were flown to the office in January, and not given official letters with offers until June. I started almost a year after my first interview, and this was their standard process. The on-site interview was 7 half-hour interviews with mid to upper management. They have questions with standard themes like "tell me a time when you were challenged..". The standard stuff. It's exhausting, if nothing else. After the unofficial offer, they were holding out on giving official offers because the CFO wouldn't approve the budget, but they "promised" there should be jobs. It's a mess in HR... at best.