It's not good in the way a good novel is good, but it's good in the way good fanfic is good. I don't mean that as a jab at Devin Grayson either, because...what I consider really good fanfic with those characters is rare and wonderful. I just think if you're going to read it, you shouldn't expect Neal Stephenson or Charles Stross. Expect a fangirl who's story is equal parts talent and personal canon.