People say the Audi A8L is inferior to the BMW 7-series because it lacks the driving dynamics and name recognition. Not to mention that the Audi doesn't sell nearly as many A8's as BMW sells 7-series.
If we look a little closer we can see that the Audi A8 has dominated the BMW 7-series in comparison tests where the two cars are involved.
The 7-series usually earns praise for its driving dynamics and handling.
The A8 gets positive remarks regarding its incredible interior furnishings along with finish and an easier to use/more intuitive MMI system. It's striking but conservative exterior design doesn't take getting used to.
In conclusion, some on this site may say the 7-series is a better car only because it sells more and has a BMW badge on it.
Actual car enthusiast insiders on the other hand know that the Audi offers cleaner exterior design, an arguabley more luxrious interior, the best materials quality, easier to use ergonomics with MMI and pretty decent handling.
The public may think they are driving the better luxury sedan with the BMW 7-series, but according to car magazine reviews and comparison tests the fewer number that drive the Audi A8 will probably not go as noticed, but they are driving an all-around better luxury sedan if looked at from the car magazine tests/reviews perspective.