It's a Victorian version, but I'd describe it as a mix between the Ritchie Movies, Sherlock, and the old Russian Holmes tv series. The first episode, entitled '221B Baker Street', seems to be a loose adapation of 'The Adventure of Black Peter' (which I haven't read, but I just confirmed my theory by wiki's summary). Holmes is sort of adorable, with little glasses and tics of hands. More of a geek than I've seen him portrayed before. He's not warm and fluffy, but he's not entirely cold, either. Watson is a nice mix of comic relief with a genuine, fierce capability. Mrs Hudson's casting is a bit out of the ordinary, and I sort of wonder where they might be going with it.
Overall, quite enjoyable, if a bit lacking in chemistry between Holmes and Watson. That might improve as time goes on; they didn't really get a lot of time to be friendly, as there was too much establishing going on.