The interview process was more difficult than I expected it to be, but in a good way. I have worked at Microsoft for most of my career and interviewed well over 500 people over the years (both internal and external candidates). One of the greatest challenges that I have found is that by the time a candidate reaches the hiring manager they were not properly vetted or prepared for the role that they were applying for. The Emergent interview process avoids this entirely by structuring their interviews in the proper manner.
Emergent Software does have a difficult interview process, and this is absolutely a good thing. If you are looking to interview for a product management type role, I strongly suggest that you study Agile project management. This is a fundamental skill that is needed for the role, but also the interview process, and you will be tested to see if you know and understand it.