It was professional and courteous. I had a first call with their recruiting person which covered the basics, and was a simple pre-screen. Afterwards, I had a one-on-one call with the CEO. That second call was a mix of friendly chat, info about the company and technical questions from him. In the end, it was pretty apparent that I wasn't their target candidate. IMO I'm very focussed on end-user concerns, whereas they're looking for people working closer to (and more knowledgeable about) the hardware.