It was an excellent movie, and I definitely intend to own this on DVD when it comes out. The way the Guy Ritchie film was advertised as a blockbuster action adventure, I feared that the characters might not get much development, but I was wrong. I was surprised and delighted with how good it was. For me, it was like on the level of Without a Clue, for fun, humor, and style.
More spoilery details below.
The Holmes and Watson relationship was pitch-perfect, with the right amount of subtext mixed in all their scenes. They bicker and banter, and know each other so well that they can push each other's buttons. That's one of the things I loved about the Holmes/Watson portrayal in the Ronald Howard/Marion Crawford series. Watson is always ready to save Holmes's bacon, even when Holmes is being an irritating jerk.
I also enjoyed the inclusion of a dog named Gladstone that Holmes was always experimenting on. It was a bulldog that reminded me very much of the dog Toby in the Russian Holmes series, who appeared in The Agra Treasure. It makes them look so domestic when they argue about the dog's ownership. "You experiment on my dog--" "Your dog? It's our dog!"
Irene Adler was pretty good too, and I'm glad they did not include the scene (shown in the trailer) of Irene dressed in some tarty corset and attacking Holmes while he says "Behave." She was dressed rather modestly most of the time, and even got to walk around in male costume. It amuses me that the only time Holmes kissed her lips, he was drugged.
At first I believed that I was supposed to just accept the supernatural elements of the plot, but just like HOUN eventually revealed that the dog was not a beast from hell, so too do we get a final scene where Holmes reveals that all the magic stuff had a rational explanation. So that definitely is in the spirit of the canon.
I look forward to seeing the sequel and can only hope that it's as good as this year's film.