I'm in the same dilemma. My wife would love to drive around in a "new to her" Audi. I know they are NOT the most reliable cars on the road. I am an auto enthusiast, so maybe (CPO with warranty would be a must), but most likely not. I told her she can get it , but it would be HER money that buys it and maintains it. However, if it were a Lexus, then I would pay for it no questions asked.
A couple of years ago, a Doctor (whom I've known since I was a toddler), wanted to purchase an SUV and it was between an ML and RX (2007). He decided on the ML based on: 1) he figured it was German, so it must be good, 2) looks. He didn't like the Lexus, but he knew it would be a reliable car and smooth. Fast forward, oh, I dunno, 5 years and he regrets getting the ML. Small quirky things fail, it's not as plush as he thought it would be, yadda yadda. My father has had an RX (2001 and now a 2010) and basically has never had any major issues with either of them. The 2010 RX350 he has now, is like my 07 Civic, CRAZY RELIABLE which is great for us who HATE paying for repairs. They are relatively less expensive to maintain (compared to Benz/Bimmer) and really grow on you. But, if you MUST have that "I NEED TO FEEL I'M DRIVING A TANK FEELING", go for it. But be prepared to PAY for it and don't whine about it since you have been warned by many.
I'm partial to Lexus as our family has had them since 1991 (LS400). Yes, they are boring and don't have the latest and greatest gadgets the Germans offer, but who cares. Lexus fits my definition of what constitutes a "Luxury Car".