What does it share? Headlights? Lots of manufacturers (lamborghini for one)are sharing bits and pieces, people don't say they're not cars because of that. Do you respect the Koenigsegg that much less for using a ford based engine? If the headlights work well, why not use them? They'd be cheaper and easier to replace when they burn out.
I understand the skepticism of the design, but you're assuming that because it's a small american manufacturer it's going to need more maintinance and upkeep. I've never heard that to be true, though, and don't want to jump to conclusions just because the company is what it is.
I've actually read a couple of tests that said the Veyron in top speed mode (the whole point of the car) didn't track very well, and that little cross breezes induced a bit of drifting. Never heard anything similar about the SSC. Despite the fact that everyone assumes that any body which reaches those speeds without a wing rising out of the back will generate lift (such as they vetyron which was not originally designed for those speeds) the SSC does generate downforce and actually has a phenominal suspension setup which allows it to handle very well. Which is part of my problem with assumptions in such matters.
I don't see how a Veyron would be easier to drive around town than the SSC. There's not a ton of size difference, and they both have similar clearance, so if you're willing to drive a veyron somewhere, why would the SSC pose a problem? It also comes with a nav system, if you require that sort of thing in your super car.
Since the SSC is not being sold as a kit car, it does have to meet the same crash saftey and emissions standards as any other car on the road in the US.
The Veyron is a remarkable achievment. But the SSC does everything the Veyron can do, albiet with less flash, for a fraction of the price. Which makes it just as, if not more, remarkable. The only problems I see with the SSC come down to snob appeal, which it doesn't have. I'm not sure that any car built in the US will have that appeal, to be honest. The Saleen S7 had similar problems, bit it too is a very remarkable super car.
I'm not saying the SSC is my favorite supercar, but it does ddeserve more respect than it gets. And certainly the Veyron is not the greatest supercar ever or even of the decade just because it's more useable than an racecar (just about everything is) and has the second highest top speed.