I’m even more confused now as the rcd330 sounds like the best option but is the cheapest? It sounds like that’s exactly what I’m looking for as well. Are they genuine vw units or after market?
They are genuine Volkswagen OEM units but intended for the Asian markets only, still that doesn't stop you from importing them and fitting them into your car. As you've noticed they are great value for the money, you can get a App Connect ready unit for around £130, even less if you can wait for the special offer events on AliExpress (I got mine for around £98 but I had to pay import on top which makes it around £115).
I'm happy with my RCD330 unit, it does pretty much all I need with lots of music options, built-in phone connectivity and on the go Google Maps using Android Auto. Plus it doesn't look at all out of place as it uses the same fascia fittings and backlighting like any other Volkswagen.