I certainly use mine all the time. It was a pain being in the centre console until I got an Air Clicker from Griffin Tech and put that in the ashtray for easy access. So now I am wired for sound... that is until BMW get their act into gear and release a proper iPod interface that interacts with iDrive/the Radio.
Sound quality is certainly good, and orders of magnitude better than the Air Tunes FM transmitter.
'05 E90 325i 6sp Man SG 118,032km on the odo (retired) | '06 E90 325i Step SG 121,021km on the odo (retired)
'08 E90 325i LCI Step SG 130,024km on the odo (retired)
'13 D30 328i M-Sport Step | EB II | Black/Aluminimum | Pro Nav | Xenon HBA | Lane Change Assist 24,760km on the odo