I have a 2015 Q50 and it is a very fun car to drive and it looks great IMO. If possible try to get them to throw in an upgraded rim package as the upgraded rims look very nice. It has had 2 recalls for software issues but vehicle itself is driving great. Can't speak on the Audi 6.
Had a BMW 5 series in the past and loved it but it had so many issues and in all honesty the Q50 is more fun to drive due much to having the ability to personalize your driving preferences. I've had the Q50 for just about 2 years and it has performed great and we've been very happy with it. 2 touch screens with a voice recognition system that works well and solid sound system. For the price it's hard to get a better all around package IMO. Hope some of this helps.