In all fairness to BMW, the S8 outguns any 7-Series from the BMW factory significantly just as the AMG S-Class variants do. It takes Alpina to compete with the S8 and even they can't get enough out of the 7-Series to keep this one close. The S8 stomps it running 0-60 in 3.5 seconds versus 4.3 for the B7 and the 1/4 mile in email@example.com versus firstname.lastname@example.org for the B7. Almost a full second in the 1/4 mile, that's a beatdown.
What makes this worse is the B7 is rated at more horsepower than the S8 with 540 on paper versus Audi's 520. That looks nice but in reality the S8 puts down more horsepower at the wheels with 479 at all four versus 414 for the B7. Audi's figure is underrated and Alpina's is overrated, despite Audi routing power to all four wheels.
Handling is also in Audi's favor with a better skidpad and figure eight result. The Audi even starts out cheaper at $110,895 versus $128,495 for the B7. The S8 even is lighter despite its all wheel drive. Get the B7 with the all wheel drive option and the car gets absurdly heavy.
Say what you want, Audi has significantly upped their game and is now routinely beating BMW, the former gold standard, in comparison tests. Frankly, it's a good thing. BMW clearly has lost some of their magic as of late. Keep up the pressure Audi and you will convert even the most hardcore of BMW fans, even the one typing this sentence.