Doesn't dock properly with iPhone 4 - maybe it's not meant to - but it continually falls out of the dock connector and interrupts playback. Also, the FM signal strength is abysmal. In the car - acceptable (just) but there's more background hiss than there should be, whatever frequency is selected. In the house, unless you're sat right next to the receiver - like, within a foot, which kinda defeats to point - this "transmitter" just can't cope and the signal disappears.
Poor product, look elsewhere