First interview with a peer, second interview with another peer, third interview with yet another peer and finally the hiring manager interview others have experienced.
All of the first three interviews went fairly well and people were very friendly and sociable, and asked good questions about my experience and offerings to the position. However, over the weeks of interviewing it became apparent there were disruptions going on with what they were actually looking to fill. The job title changed three times, and by the time I got to the last interview the description wasn't even in line with the original post - they were looking for a project manager, not a product manager. It is rather frustrating to commit this time when they haven't sorted out what position they even want to fill yet. At any rate, everyone was friendly and sociable at the outset, so I didn't have any problematic experiences there like others have said.
Sadly, though, I can mainly confirm the weird organizational goings-on described by other posters. Although, I don't think I feel as strongly as others do. The interviews themselves were perfectly fine, but there's obviously other challenges going on behind the scenes that you may not expect from a company like this.