I ended up with the s900c for £199 - best fit for me by far due to the air-pumped cheek pads. The fit is so good that I can't get it off my head with the pads pumped up. Andy didnt even know this technology existed! Not sure if I would trust it. I mean its obviously safe, but I would be scared I would pop it! When I asked about the longevity of this technology, the sales assistant said that they have never had any back, nor heard of any problems. Not sure if this is just sales talk though. I took the lining apart to have a look and it does look like the air bladders are made of a strong material. Only time will tell though.