I think that I am too much of a purist. The chemistry between Holmes and Watson was just plain wrong in the first movie.
That said - there were
some good things -
Costumes, aside from Irene Adler (and she has a bit of an excuse). Much better than Coppola's Dracula.
I could pinpoint the year by the construction on the Tower Bridge.
They remembered the damned bull pup! (No one remembers the dog. Mentioned only once in the books, as I recall.)
Scoring was good. (I did not like the movie, but own the soundtrack.)
I liked the fact that they remembered Holmes knowing martial arts, but hated the implementation.
Aside from the terrible chemistry between the chief protagonists the things that I disliked are too many to go into... and folks here seem to like the film.
So, I will watch the sequel, and most likely complain about it.

Then I will sit down and watch Brett. Again. (I have an awful lot of Sherlock Holmes in my DVD collection, some of it much worse than this one.)
The Auld Grump