3-Stage.
1) Initial call with some technical questions.
2) Build a solution to demonstrate good design choices and SOLID
3) Final face to face - more technical questions
The first two stages, I answered and was deemed a satisfactory applicant.
The first stage was an overall discussion of how one approaches their work, as well as some C# questions that any senior worth their salt should have no problem whatsoever answering.
The second stage I particularly liked (despite it being very time consuming) because it requires demonstrating how a person approaches a problem - TDD is very important to a PC, which also goes to show they are a company that keeps with present times.
For the last stage, however, I was interviewed very strongly on technologies that did not exist on my CV. This included a lot of the interview's focus (design an app on the board from the ground app, how to handle high volume of guests, MQ frameworks) on things I had never worked on nor had claimed to know which I found unpleasant and frustrating - I could very well have been applying to be a master chef and I'd know just as much about how to make my own creme brulee. If anything, I think that the one thing Perfect Channel could do would be to better screen applicants before the 2nd and 3rd stages, to be sure they have all the required technologies prior to calling them over.
In the end I did not get an offer, nor did I get any feedback (which is my one real complaint, since I had dedicated a long time on the 2nd stage interview), which would've been beneficial to me as a candidate.
That part aside, however, the people were friendly and the company has that certain beautiful feeling of a company trying to make a difference. I really do wish I had gotten an offer, because I otherwise only had positive vibes from PC as a company ! I would definitely recommend it based on the overall feel to any applicant :)