I bought this item as it looked well designed and it was well priced.
The 30pin car charger for the iPod was fantastic; it works really well (perhaps the best on the market).
However, the rubber holder which goes into a cup holder doesn't work with iPods
The space in the middle does allow the charger to connect, but due to the location of the headphone jack, the design becomes faulty and the holder doesn't work properly.
As for the tap thingy - I don't know, I haven't used it....
A great product if you have an iPhone 4(S)