I am watching both at the moment. Started watching the US version and now watching the Danish one. Will have to be careful after this week as I think they start to catch up and if the Danish one is being shown 4 nights a week it will spoil watching the US.
The Danish one is much more drawn out, with other subplots and details (the girl's injuries etc.) and it is 7 episodes longer.
Really like both, and I think the acting is superb, I think the US version has the best actors.