I have a complicated relationship with Jack the Ripper fiction. I really want to like it but I rarely do. In fact, the only one I really enjoyed was Melanie Clegg's From Whitechapel and you could argue that it is more a novel that uses the case as background than an actual Ripper-novel.
My track-record with Holmes meets the Ripper fiction is even worse. In the best case, I found them totally forgettable but mostly they were so horrid that I wanted to rip them into little pieces.
Dust and Shadow is different. I love it. It's a great Holmes-pastiche. Faye catches the voice of Watson perfectly. I also didn't feel that her Watson was too stupid or her Holmes too cold, both are things that often ruin Holmes pastiches for me.
It's also a great fictional account of the Ripper killings. With the focus on fictional. I don't mean that Faye didn't do her research (she definitely did), but in reality, there was no Sherlock Holmes involved in the investigation. The fact that here he was does change some minor things because the Ripper reacts to Holmes' involvement. I think only absolute purists can object to the way this was handled. I found it very well done (and I have often grumbled over stuff like this ^^).
The whole subject is also treated with the respect it deserves. Of course, this is the true story of the brutal killings of several women and you can certainly argue that it is always ghoulish to read/watch/listen/play anything inspired by something like that. I know that there are people who wouldn't do that under any circumstances and I am aware that my enjoyment of these stories might be a bit questionable...
But there are different ways to treat this case (I actually read a story once in which the author thanked Jack the Ripper in the foreword because he inspired so many authors...really). This book never forgets that the victims were people and the characters act accordingly.
Then there is of course the question of the ending. It won't be a spoiler when I tell you that this book doesn't stray so far from the historical facts that the Ripper is caught and everybody is happy. I've seen various ways the question 'Why didn't they say anything when they knew who it was' (if in fact they found out...) was handled and I have to say that I liked this one best so far. It made sense and was not out of character for Holmes.