This product is well thought out and very easy to use, and provides excellent sound quality through Bluetooth A2DP via your car stereo AUX-in socket.
Physically it looks like a cigarette lighter socket charger, but with two leads running from it. One of these leads plugs into your AUX socket (and can be shortened to prevent trailing wires if your 12v and AUX sockets are close together), the other lead ends in a disc shaped button that also contains the microphone and status light. This button is magnetically attached to a disk that you can stick wherever is convenient, allowing you to easily remove the whole unit (eg. to store in the glove compartment). Additionally, the socket part also has a USB slot, so you can plug in your phone if you need to charge it - useful !
Once paired, all you need to do is press the button/mic once to connect, and again to start or stop music playback. Remember to set your car stereo input to AUX too. The button illuminates orange when un-connected, and blue once connected. If the phone rings, you just press the button again to answer the call (I think a long press will reject it).
I found the sound quality to be excellent - I could not distinguish between using the AirCast from plugging my iPhone into the AUX socket directly. It really is very useful to be able to jump in the car, press the big button once, and once again, and have music playing without even having to take the phone out of my pocket !
Speech quality is acceptable via the mic, but that will be dependent on how much background noise there is in your car. The only slight negatives I can think of are that phone audio is of noticeably lower quality (not a fault of the AirCast, but the phone networks) and Siri is pretty much unusable over the AirCast - but I think that's mainly because of the 'telephone quality' audio and car background noise.
Just bought this a few days ago. Quite happy with this little gadget. I'm using it with an iphone 5 in a bmw e92. So I have my aux input and cigarette lighter under the centre console which is quite handy. The wire fits under the lid when closed and I attached the main button just beside the centre console so no wires can be seen at all. Very easy to pair. Took a minute and from then on it automatically pairs. I just jump in the car, start it, hit the button to pair it and then hit it again to play music.
The only little snag I found with it is the double tap to go to next song is quite tricky to the hang of. At first it would just pause the song. Then I read somewhere online in another review that you had to double tap slowly, in fact to the beat of the song "staying alive". Which sounds a bit weird but actually works ! Im just used to the quick double click of my iphone 5 headphones. So maybe will take longer to get used to it.
I haven’t used it for many phone calls yet, seems to work fine. Also Siri does work it you hold down the button on it, although im not much of a siri user so havent used it that much either. Mainly bought this for music and compared to sticking my aux cable in and out of my iphone it is much better. €70 is probably a bit steep, but it does exactly what I want so I had to pay ! would recommend.