Hmm. My Nokia 6230 seems to be fine on Bluetooth with 3.15 firmware. I don't have a headset though. So far I've just been using it with a USB bluetooth adapter (Billionton/Cadmus).

Has locked up once or twice but it's still been pretty good overall. Better than other brands I've seen

Battery life isn't fantastic. No Bluetooth and minimal calls sees a maximum of about 3 days battery life. Not too good IMO.