Gateway is the canbus gateway, older Mk5's original gateway cant switch off the newer head unit fully - meaning battery drain.
To be fair, the Xtrons has been OK, but there is zero support from the manufacturer - I deliberately got it through amazon in case anything went wrong.
I was hoping for a seamless working music/radio/navigation - but it really is trial and error trying different apps - these apps can sometimes crash.... or get removed by google... or need updating... its about 15% more nerdy than I would like.
But - Torque app is great for digital dash and error code reading/clearing.
There is a Chinese Android head that is OEM VW - heard good things on the forum
If you want something more plug and play and works out of the box - stick with the mainstream manufacturers - I don't think they make one specifically shaped for the Mk5, you would need a facia adapter and it will be a smaller screen - but you may still need an updated canbus.