I was brought in for 2 rounds of extensive interviews. Strangely, HR was not involved in the process whatsoever (from what I could tell). There was no formal schedule of interviewers - that part lacked organization - but they made a strong effort to see as many candidates 1-on-1 as possible. At least 4 interviews each round. Came away with a positive impression of the people there. Work culture seemed a bit intense, but that was expected. The negative part was a lack of communication after the interviews - I eventually did hear from them but I had to make several calls to get some answers. Despite some improvements that can be made to the process, my overall perception of the group was positive.