This was the most efficient and painless interview process I have been through. Everything moved fairly quickly, and there was always a clear picture of what next steps would look like. There were four interviews before the on-site, but one of those was to connect with people who would not be there in-person for the visit, so that seems like a reasonable number. The recruiters are the most responsive and friendliest that I have dealt with; there's no doubt that working with them was a highlight of the experience. They also very kindly offered to have a call with feedback after they declined to make an offer (but essentially of their feedback was positive, so I'm not sure how much I could glean from it; still nice of them to offer).