I got a couple of these on sale, but I still haven't cracked the packages open, because when I got home I read that some people had problems with the iPhone 3GS had connection problems with this particular headset. I don't have a 3GS (I have the original 3G), but nonetheless I'm not keen on keeping this headset if it has continued problems with other iPhones.
Is the Sennheiser VMX100 still an issue with the latest iPhone OS 3.1? If so, I'll just return the headsets unopened.