Personally I like the RNS310/315 as it keeps it quite simple and gives you your bluetooth and sat nav in one convenient bundle and think it looks nice in place, and come in around £200-260
Next easiest is the RCD 330g, it's similar and cheaper but can be buggy from some reports such as can't work with mfsw and no radio stations, but you get car play if that's what you're after which allows you google or apple maps and bluetooth. They are around $100 + shipping and tax
More pricey end is the RNS510 which gives you a 6 cd changer and maps, but you need an external bluetooth fitted, but it does look the part and come in around £400-600. Similar to this is the RCD510 which is the same except there's no sat nav and these come in at around £150-200
Then there's aftermarket units generally people go with Pioneer car play units but are more expensive than the RNS310 around £300-400. But won't keep it looking completely factory.
You'll need a microphone for all of these except the aftermarkets and RCD 330G, I recommend a genuine VW microphone kit, the fakes never worked for me.
