I've got an R8 V10 Manual Spyder and it is perfect. Build quality is awesome and it truly hasn't had any issues. Audi Service is cheap. The V10 grunt is unbelievable. So far I'd say its one of the best cars I've owned. Roof comes down too.
My 10plate GTR was crap build quality, overheating gearbox oil, power steering bust twice, dash rattled from new, brakes cracked, stupid & expensive service intervals and the "limp home mode" nearly cost one of my friends his life while overtaking in his 09 car. The seats are too fat, should have foldable carbon buckets.
However, I would buy another one as I know they have improved over time, the R35 is truly a gorgeous car and certainly one of the quickest out there. Bang for buck it has no rivals.
The guy who started this thread should try the V10 Coupe but manual only.
R-tronic is pants, the latest cars are awesome but still very expensive.