I just finished two Sherlock Holmes pastiches, back to back -- though one was a short story. The short story was also closer to being a parody, while the novel can stand on its own,
"A Study in Emerald" is, as the name suggests, closely tied to A Study in Scarlet, the first Holmes novel, as well as Lovecraft's Cthulhu stories (I'm guessing at the part, but it seems to fit). As much as I enjoyed the story, most of the fun comes from looking at the way Gaiman has twisted around the original, and I'm not sure it would have any interest to someone who'd never read it.
Laurie King's The Moor is less tied to the source material, although she draws heavily on The Hound of the Baskervilles (I get the impression that other books in the series are less directly drawn from Doyle's originals). But she gets to eat her cake and keep it too, as far as going her own way; she has Conan Doyle as an off-screen character in the novel, who has chosen to write about Holmes's adventures, and has sensationalized them into the bargain. This allows King to jettison pieces she doesn't like as being Doyle's invention.
On the whole, it works very well. King's narrator, Mary Russell is a good partner for Holmes, clever enough to be interesting, but not a Mary Sue who constantly astounds him with her own wit. (I must admit to a bit of trepidation on this score before starting the novel). Although King doesn't present us with Doyle's Holmes, exactly (he never pulls one of those "this mud is of a yellowish color that one only finds within these 3 specific spots in London, as you would know if you had read my monograph on the subject" moments), she has clearly read the originals. There's a funny inversion toward the end where she talks about him "rummaging through the lumber in his store-room of a mind" which can't be coincidental. On the other hand, I would find this a book easy to recommend to someone unfamiliar with Holmes in general, which definitely can't be said of "A Study in Emerald" -- if you've never read A Study in Scarlet, it will have no resonance whatsoever.