When I was looking to upgrade my headset, I also was looking at the S1 Passive. The performance was ok in terms of value for money but it sat really weirdly on my head. Bearing in mind that the way it fits will determine the comfort of your flight, I would seriously recommend you trial all headsets before making a choice and select the one which feels most comfortable.
After all, what's the point of saving €100 only to regret it after an hour's flying? I tested DCs, Sennheiser, Bose and low cost brands before finding that the Lightspeed Zulu fitted my head best and ended up with a set of these, 4 hour trips with them are not an issue.....