Being a moderate fan of things Holmesian, I thought Downing's second installment was quite a bit stronger than the first. He and Law play well, and the new movie doesn't suffer from the CGI'd Steam Punk Nonsense of their first outing.
The two Downing/Law movies do have elements borrowed from various stories. I think that is another element contributing to their success.
I would have to disagree with Don_S: There is a strong fan/cult following of Holmes, and quite a few people would pay to see a more direct translation from book to screen. That said, I don't know if they could make enough money. As a period piece, production would get a little pricey.
Speaking of TV movies, I would suggest the four Hallmark productions with Matt Frewer as Holmes. They are available on DVD.