I've watched both the British and American versions of Being Human. They are a more grown-up version of the many vampire and werewolf shows out there, but not as "sexified" as some of the others. I enjoy both versions of the show, but the American version really hits the mark on a great show. The British version had too many cast changes that negatively affected the plot, and caused, I would say, writing problems. The American version has been able to keep their characters, and really keep developing their relationships. There are many episodes of the show that have pulled the strings of my heart and really made me feel for the characters and what they are going through. The actors have done a great job being realistic and convincing in their made-up world of vampires, werewolves and ghosts.
Another good aspect of the writing in the American version, is that all of the plot twists are well thought out and well explained; opposed to the British version, which left the viewer a little confused at times. Season 3 Episode 1 is an example of this: in the British version, I feel Sally's departure from limbo as confusing, but in the American version, they give a feasible reason as to how Sally could depart from limbo. Well, as feasible as a witch bringing back the dead can be.
Make a point to try this show out. If you enjoy vampire, werewolf, or ghost TV shows and movies, than Being Human is an interesting and entertaining perspective on the world of monsters.