Audi A4 is not a luxury car, it is just an ordinary German sports sedan, just like BMW 3 series. What sets it apart from your usual Japanese fare like Honda Accord, which is incidentally a larger car than the A4, and should be compared to the Audi A6 or BMW 5 Series rather than the smaller A4, is the German way of building their cars. They are terribly expensive because of excellent engines, fine engineering, and their use of special alloys for their suspension.
Honda tried to fashion itself as the German car of Japan, but their suspension turned out to be stiff rather than Teutonic and you will notice they have lousy suspension whenever it rains, as it is more noticeable how their suspension refuses to ‘play’ with the road, but rather ‘snub’ it.
The worst thing about Honda principle of building cars is that they think they are technically the best Japanese car manufacturer, and with that belief, they are stuck with their outdated transmission, their terrible hard seats, their annoying climate control which turn on/off the A/C compressor every 10 secs or so, and a styling that’s been left behind by Toyota and Mazda.
The only reason to buy a Honda over an A4 is if you can’t afford an A4, and you’re crazy not to consider a Mazda 6. Mazda actually makes the best Japanese cars, not Toyota and definitely not Honda.