Two onsite interviews (probably because I are currently living quite close to their New York office)
First round with 6 people (2 associates, others are patent agents/technical advisors), all were very nice and friendly, no difficult questions
Second time with the two partners in the group, who were not so nice. They didn't prepare the interview at all. The first partner didn't have my CV and had no idea who I already talked to before; the second partner disappeared at the time when we were supposed to meet. It took about half an hour to find him...
They are looking for CS background (I'm in ME/Physics/Laser), but they didn't disclose this to me (nor did they put this in the job description) and interviewed me (dragged me to NYC twice) anyway. And they didn't want to cut me loose until one month after the interview...