Hi.
Do you get a valid stamp from the dealer for the service booklet (which is important for maintaining its value when reselling the car)?
Otherwise: If the mechanic is familiar with the car (has worked on that model before) and has a good reputation, I don't see any problem with it.
Es sei denn, Du möchtest später noch Kulanz bei evtl. Problemen haben. Aber inweiweit dieser Begriff noch im VAG-Wortschatz enthalten ist, darüber gehen die Meinungen ja auseinander . . .
You can get your car serviced at any workshop. However, it seems that VAG workshops generally fail to meet customer expectations less often than independent garages.