Interview Process is: HR filter -> Manager interview -> Grandfather (Manager's Mgr) interview -> Peer meeting
The peer meeting isn't conducted in an interview setting. It's more informal, adapted to the needs of the applicant. It could be a lunch or a dinner and once it was even participating together at a hackathon.
We carefully select peers against "buddy bias" and encourage diversity in the workplace.
Our company is over a period of several years very successful in recruiting and have very little turnover. The biggest drawback could be that we are "too picky" and thus (at times) have problems growing fast enough.