They said they arranged similar distribution deals in America and in Europe, so I don't see why Americans would have to wait longer.Roguey is an American.
In theory, it could take longer to ship things over there if Larian doesn't have a good shipping infrastructure in North America. I don't see why they wouldn't, though. I'm sure a large enough percentage of Kickstarter backers are from the US.
Also, people complaining about long shipping time should stick to digital versions.