Have bought a few ipod FM transmitters for various cars for myself and my wife over the year and needed a new one recently to charge a new iphone.
I wasn't sure which one to get given less than stellar reviews of all of them. I have to say though that I am pleased with this one.
The auto scan function works quickly but I tune it manually into frequencies i know are free in my area and I have found the sound quality and signal strength to be very good. A nice bonus is that the transmitter recognised the name of the album being played on my iphone and transmits this as a station name on my car stereo - so rather than the stereo display saying eg "radio 4" it says "Cast of Thousands". A nice touch that was unexpected.
What I have found is that the quality of the sound is unsurprisingly a function of the quality of the stereo and the FM aerial in the car. I have a very good stereo in my vehicle and there is little or no background noise audible when in use, but my wife's car has a poorer aerial and therefore poorer reception from the Griffin. Helpfully there is a signal boost button which does improve the strength, but the sound is limited by the quality of the stereo. Haven't tried the App that goes with it as I don't see the need.
I wonder whether some of the poorer reviews on this product are a function either of a poor quality car aerial or otherwise FM congestion, neither of which of course can be solved by the Griffin?
Does the job for me and so far so good.