If you are alone, make sure your cigarette lighter is convenient to you for easier access (depending on vehicle models, it varies. I remember my previous car where decision would not have allowed me to use this kind of kit because it was too far away while driving (not within arms reach). Otherwise, your passenger can change tracks or take the call for you if you drive not alone.
For me, the main advantage lies primarily in being able to listen to his music, bluetooth, in high partleurs of his car. I use my own Deezer or music tracks, I am always happy to listen to my playlist rather than radio ads. And for me, this little tool does the job. It perfectly fulfills his contract.
For calls, my correspondents hear me well. The microphone is located right on top of the device that is beside me in the car (cigarette lighter close). But even a little more distant, there autait been no particular problems I think.
Finally, a kit that easily give the bluetooth option without sticking to your car accessory on the dashboard. And that's a positive.