A bit tricky, but not in the traditional sense. They don't grill you, at least in my experience. The hiring manager just sold me on the opportunity and company while saying I was a shoe-in. That got my confidence inflated and then I approached everything too casually -- I probably didn't sell myself hard enough as a result.
Then I met the executive, who's really nice, but just asked really broad questions. Still, both seemed smart yet down to Earth. I really want to work at TripAdvisor someday.