To me it was a relief actually. I had a really hard time watching the first episodes at first. Just because they're almost exactly the same as the UK version - only with a bit glossier finish and, in some cases, not so good acting. ;)
When I try to get people to watch the US version that has already seen the UK one, I try to make it very clear that they have to watch at least four episodes before giving up on it. A lot of them end up giving up on it just for the similarities anyway - but if they stick it out for the first four they almost always watch the whole thing. Because after 103 it's a very different show all together.