According to Audi Canada, the purchasing split between manual and automatic transmission buyers is currently 60/40. There's no denying the benefit of an automatic transmission in city driving, and if that is where you will be driving most of the time, the R-tronic is the better choice.
And if you buying a R8 to just drive around the city, you might want to give your head a shake.

I like the looks of the R8 and would love to drive one. I noticed somebody has one for sale on Autotrader for only $180K.