I've just not read great things about the Koenigsegg in terms of reliability in general, the gumbal to name one. These things are expected with supercars, but its not like Koenigsegg have a perfect record - just some balance to Ashoks thoughts.
The Veyron is just the nuts though, far more practical than something like the Koenigsegg, what is it? 15K serivce interval with the Veyron?- it is designed ground up to be practical. It seems to me (as an engineer), that Bugatti have pulled all the stops out on this one - new engine design, transmission design, stability systems. If you try to impliment multiple uses of a new technology in one project, you will encounter problems.
To me, a Koenigsegg is just an extension of the supercar trend, "get engine, get supercharger, go to town on Carbon fibre". The Veyron is a different kettle of fish, its a daily driving comfortable hypercar. Its like comparing a mig 29 to a stealth fighter IMO.
Stu