I have just been comparing the products from Dietz and Nav TV and the Nav TV is cheaper and the audio shops around my area tell me that the Nav TV product is better quality.
For example the product is a plug and play solution and has two inputs one Audio and Video and the other is Video so i could use the one for a DVD player and the other for a reverse camera.
And from what I have gathered the Dietz product is niether.
I dont allways go for the cheaper product but in this case i think it could be best.