Overall I had a very positive experience interviewing at Yelp. I was given an offer but I ended up declining for another offer but it was a very close 2nd.
I was very impressed by the culture focused questions that were asked during the culture/team fit interviews. I found the questions insightful and helped me appreciate the emphasis they had on creating a positive work culture.
Before I had a technical interview (using HackerRank) they sent me a practice test and told me what the focus of the interview would be on (data structures - specifically dictionaries) so I could prepare beforehand. I really appreciated this as no where else I interviewed gave me a practice test or told me the focus. It felt like Yelp wanted the interviewees to succeed by providing this support.