I went on not one but two roller-coaster rides with Apple as a candidate for Sr. Mechanical Engineer.

The process went as follows, normalized from three weeks before my first onsite interview:

• 3 weeks: Received a strong recommendation from an Apple employee who had been a colleague of mine at a previous company.
• Day 0: Met with the hiring manager. I had previously worked with him as well at another company, and he thought highly of my skills and passed me on for a full-day onsite interview.
• Day 28: A full day of technical interviews from 9:15 AM to 5 PM. Each was basically 15 minutes of chitchat and 30 minutes of in-depth technical grilling, mostly problem-solving hypothetical engineering situations and technical brain-teasers. At the end of the day, the recruiter told me that if I passed this round, there would be several interviews with upper management to ascertain technical fit. Usually, the next step is likely an offer. I did well on the tech interviews.
• Day 47: After being invited back, I met with two upper-level managers and, surprisingly, two additional engineers. The latter two interviews were also technical grilling, similar to above. I did well on the tech interviews.
• Day 55: I hadn't heard back from the recruiter or anyone, so I called them.
• Day 60: The recruiter called back apologetically and asked if I would come in for ANOTHER round of interviews. I said sure, thinking this must surely be a perfunctory final interview prior to an offer.
• Day 70: Déjà vu – I met with two upper-level managers and again, two additional engineers. The latter two interviews were also technical grilling, similar to above. I did well on the tech interviews.
• Day 82: Received a final call from the recruiter: "You did really well on tech interviews, but upper managers aren't sure there is a cultural fit. Very sorry to say we will pass on making an offer. However, there is another group that may be interested, would you like to interview?" I reluctantly said yes.
• Day 91: A full day of technical interviews from 8:30 AM to 5:45 PM. Many were more cultural/situational interviews, only a few were technical grilling. I'm sure I did well on those tech interviews, at least.
• Day 101: Received a message from the recruiter saying, "Very sorry to say we will pass on making an offer, don't think there is a technical match." Uh huh. Wait...what?

In summation, a very opaque, disrespectful, and unsatisfying experience. In truth, I was a more senior candidate in terms of experience and position than most of the folks I met, and very much senior in terms of age. My time in the cafeteria was instructive – at Apple, there appear to be very few employees pushing much past 40-45. Lots of nice folks, though, and I enjoyed all of my discussions.

If you are an M.E., know your beam theory, beam bending, and strength of materials.

They cover this material extensively in interview quizzes.