I purchased this device for two reasons: to prevent having to take my phone out & plug in an aux-in line every time I wanted to drive somewhere, and to prevent having to use a bluetooth headset while still remaining hands free talking. This device promised to deliver on both fronts, and almost nailed it. It has a clean, minimalist looking design which promises to blend well with almost any car interior. It does require some wires to be routed around to get all the components in the right spots, but if you commit a little time & effort you can hide most of the wires & maintain a very clean look. The main portion of the device is a combination microphone, bluetooth receiver, and 1-button remote. It comes with a magnetic mounting base or the combination unit that has an adhesive backing for easy installation. This limits where you can place the device in your car, but the footprint is quite small so you should be able to find a place where the entire base contacts the mounting surface. So far, the mounting base has shown no signs of coming off, and my car is parked outside in the Texas sun every day when I go to work. Also included is a 12V power adapter (which has an integrated USB port for charging) and an aux-in line extender in case your 12V power source & aux-in port are not located near each other.From this point on, I will treat the unit as two separate devices to look at functionality. Also, the entire review is based around use with an iPhone 4.First, as a music interface. This device does a great job allowing me to play music without physically having to connect my phone to the car. This is good for a number of reasons. First, I don't have to take my phone out of my pocket to play music. Second, I don't have to keep an aux-in line plugged in at all times which greatly reduces wire clutter around my main console.Also, the simple 1-button interface does very well in some cases, but falls a little short in others. After turning on the car, the remote/mic unit will have an orange ring. Press once, and wait for a couple of beeps to indicate the device is connected (assuming you have already paired your phone, which was very simple & painless). This usually takes about 5-10 seconds for my phone to connect. After it connects. pushing the button again will begin playing whatever music you had playing most recently. I have been able to get songs to begin playing this way using the default music player, Amazon Cloud Player for iOS, Pandora, & Songza. I have not tried other services but I have no reason to doubt that they wouldn't work. When the music is playing, pressing the button again will pause. The included directions indicate that double & triple tapping will skip forward & backward tracks but I have only gotten the double-tap to work. When you turn off the ignition, the music pauses on your phone. All in all, very natural & unobtrusive interface.As a hands-free voice interface, things start to unravel a little bit. Again. the simple 1-button interface works well. The remote/mic unit will flash before playing your ringtone through the car speakers. Tap once to answer the call. Tap once again to end the call. The instructions include information about call waiting/handling multiple calls, but I have yet to investigate these features. There isn't really any need for additional functionality.The sound quality of the calls is substantially worse than the music (which is pretty darn good). This isn't a huge issue, but since this is being used in a car where there is going to be a large amount of background noise, being able to hear the other end of the line clearly is extremely important. Also, you really have to mount the remote/mic unit somewhere that will be directly in line with your mouth to be heard clearly by the other end. This only becomes an issue if you don't have a convenient mounting location for the base (as mentioned above). My only good mounting point was towards the right of the center console, and I have been told that I don't come through clearly sometimes. I usually find myself talking much louder than I would in a normal phone conversation (borderline yelling on occasion). If I have a passenger in the car, they come across much clearer, so I plan to move the mic somewhere closer to my seat once I find a good mounting spot.UPDATE: Moving the mic to the driver's side of the console has cleaned up the sound quality on the other end of the call. I have been told that there is no noticeable difference between using this mic and the phone mic. See uploaded picture for different placements.Overall, this is a good product. I would give the music player side 5/5 stars, and the phone side 4/5 stars. Also worth noting is that the price of this product has fallen $10 since I bought it ($40 at the time of posting this review) and I still feel like I got a good product for the price I paid.