I've been battling call quality issues with bluetooth headsets on iPhone 4 with IOS 4.0, 4.1 and now 4.2.1.

The main issues have been call quality when using a headset – very weak sound quality. I've tried a number of headsets with similar results, but my main headset is a Sennheiser VMX100 that is (a) listed/sold on the apple store site as iPhone4 compatible, and (b) known to have worked very well with previous non-Apple phones.

Secondary issue (until 4.2.1 upgrade) has been call handling and BT disconnects. The phone and headset frequently lose connection and randomly reconnect later.

After the 4.2.1 upgrade, I can initiate a call via the BT headset, but the call proceeds to connect via the iPhone – I need to manually transfer the call to the BT headset once the called party answers. This is (a) unsafe in a car, where you rely on voice dialling, and (b) inconvenient due to delay in getting to talk to the other party while call transfers to headset.

I haven't had reliable enough BT use to see whether call quality has improved, will update on that later.

I've reset network settings, removed the BT headset pairing from phone, restarted phone, reset BT headset to factory, reconnected/repaired without getting this to work.

This is a serious problem for my use of the phone. Is anyone else experiencing a similar issue?

Nick.