As others have said go for the proper VW kit, you should be able to pick them up fairly cheap used on various VW forums. It will look much better and will help to sell the car when it comes to it, rather than some 3rd party headset.
No issues here indeed. It is Android, so there is an element of knowing how to set everything up involved. but it's not rocket science either really.
These units offer far more scope than any OEM navigation unit or stereo.
The one I have is of no use to you as the unit is shaped to fit the E46 only, but you can get the same internals in your car's specific fit. Look for ones from makers like Eonon, Erisin etc for your car model in the search field. they all run Android (now on version 6 or 7) with 2GB RAM and at least a quad or octa core processor.
They are in the region of £280.
Waze, Google Nav or whatever you prefer. I use Waze. Mine has a 4G dongle connected via USB and a 128GB stick for music. You have the Play Store so you can install any app. It's essentially the same as having an Android tablet but focused on car use. You can replace the default homescreen with whatever you prefer. Mine is fully customised like my phone using Nova Launcher.Hi mrk, what nav system do they use? you say they are android so could you use Waze on it for example?
What do you mean, least likely to consider what.. ?If you are "well into your entertainment" then this is the least likely thing someone who was "well into their entertainment" would ever consider. Ever.