I interviewed with Airbnb earlier this year. The process involved one phone interview and seven onsite interviews, taking about two months overall. It's not significantly different from other tech companies, but there are a few aspects I really didn't like:

• During both the phone and onsite interviews, there was very little interaction with the interviewer. They seemed to expect you to come up with the solution and write perfect code, no matter what. Furthermore, the interview questions themselves were sometimes not interesting at all.
• There were two "culture fit" rounds. While nothing surprising, Airbnb had its own cultural issues (a few months back, in China). Based on my interactions with some of the interviewers, the experience was definitely not enjoyable.
• The tech challenges at Airbnb are not particularly interesting if you're looking for hard problems to solve.

Design a K-V store.