Well, I have to admit, I only started reading the Sherlock novels after having watched the BBC interpretation of Sherlock. While I still think of Benedict Cumberbatch and Martin Freeman while reading about Sherlock Holmes and John Watson, the TV series and Doyle's novels cannot be compared in the slightest aspects. Doyle's talents can be found in the mysteries he manages to come up with rather than his characterizations, creating a lot of free space for Mark Gatiss and Steven Moffat to come up with more sophisticated and interesting characters. This doesn't mean, however, that the Sherlock Holmes novels aren't interesting to read. 
 "A Study in Scarlet", the first installment in A. Conan Doyle's "Sherlock Holmes" series, introduces its main protagonists Sherlock Holmes and John Watson, weaving an interesting mystery around a complex case while also including both suspense and humor. The second part surrounding the story about the Mormons, which was supposed to give a lot of background information on the murder mystery, felt long-winded due to its lacking ability to make me as the reader sympathize with its main characters, especially as Sherlock and John were missing for nearly the entire second part. It certainly wasn't bad, but may feel a little weaker than the scenes surrounding Sherlock and John in their investigations.