Audi R8 V10 Performance
You can actually USE the Audi. The Senna is a big car and terrible on the road. I'd like to be able to take my exotic to dinner and not have to worry too much about street parking. Not to mention the difference in price! You could buy the R8 AND a GT3 race car with a truck and trailer for the price of 1 Senna.
Looks would have to go to the Audi R8, But in terms of performance the McLaren Senna is superior.