I enjoy the concept of solving the case in the first half and discovering the backstory in the second, but I liked one more than the other.
In the Holmes-focused part, there was an interesting mystery with a nice twist and Sherlocks's chemistry with the other detectives was delightful. The second half focused pretty much on a crime syndicate - not a favourite premise of mine - and featured no characters that really aroused my interest. Still, I was never bored. The freemen lodge Idea was kind of unique and I like that in Doyle's stories, America really feels like such a far off place, so different from England. The atmosphere is spot on in both parts, but this is my least favourite Sherlock Holmes book so far.