I didn't think I was going to enjoy this when I first started it; I'm not into the paranormal at all and I wasn't sure about the time shifting aspect of the novel. However, as I started to read, I really got into the story and found myself reaching for the book for "just one more chapter".
I preferred Hawise's story to Grace's, certainly for the greater part of the book - the author has obviously done her research and really brought Elizabethan York and its characters to life - and I was almost skipping through the next part of Grace's story to get back to Hawise. I did start getting behind Grace's story towards the end though and the last few chapters had me riveted.
Just checked the author's blog and it seems she has a second novel on the way, due to be published this year and again set in the present and Elizabethan York. I'd definitely give it a go, even if just for the historical part of the story.