I didn't watch Grey's so this review is unbiased in that regard. This movie is great, however, on its own. It's clean, well thought out, has good character development and storyline, and is a good psychological thriller, which all paranormal stories should be. There could be a little more spooky, and maybe a little more delving into Amanda's past and the trauma she is working to overcome, but aside from that, I have no complaints and will gladly watch it again. Excellent acting by all, good story, thumbs up!