I recently finished the Sherlock Holmes novel, “The Sign of Four”. It was along the same lines as A Study in Scarlet in that it was a reasonably enjoyable read, but not as good as I had hoped.
I find the TV series Sherlock far better than the books. The novels are just a bit boring in comparison. Once I have suspended by disbelief as to how clever Sherlock could be, he might as well be insanely brilliant (as he is in the TV show) rather than rather brilliant as he is in the novels.
A common theme between the two novels I have read is that the mystery does not actually take up that much of a novel. But during the explanation, it will suddenly go into a huge back story that goes on for ages.
Finally, I also found the end a bit of a let down. I did not actually feel like anything was resolved. On balance, I enjoyed it more than I did the first novel though, so I am hoping it will continue to get better and better.