The US wasn't too bad. The most annoying thing to me was the new names. It's not like this was originally a Japanese show with non-anglo names. What was wrong with Mitchell, George, Annie, Lauren, and Herrick? Kept confusing me when they referred to people by names.
If the story lines were different I could see it, but the US pilot followed the British pilot exactly. So why change the names?
btw, Series 3 comes out soon in the UK. BBC-A will probably show it quickly, as they've been showing things almost at the same time as the BBC lately.
While the Syfy ones seems okay, if you've seen the BBC one, it might not be worth the time as they're just using the scripts from the BBC. It appears that the first season will just be the first 2 series of the original (based on the previews of the upcoming season shown at the end of the first episode, I recognized about 4 or 5 episodes scenarios from the original show). If it was being done differently it might be worth the time, but not if it's exactly the same.