Mine is a local chinese made A2DP one (bought from deal extreme) and my roomie's is a original nokia one (single ear) he had got with his 5800.
I am 100% sure there is no problem with the headsets. I have a sony ericsson w800i and it perfectly pairs with both these headsets.
I think i read somewhere that there is problem with pairing of BT headset with some symbian phones.
