The good bits - the sense of period was reasonably well captured, and it began with some genuinely frightening scenes. The minor characters of the Barrymores and the convict were also very well done.
Unfortunately, it was all downhill from there, Richard Roxburgh was an uninspiring Holmes. The relationship with Watson was clearly misunderstood, and personally I found his rather surly characterisation irritating, Dr Watson is supposed to be conduit for Holmes' brilliance, so us mere mortals understand what is going on not to behave like a spoilt schoolboy made a mockery of.
The character of Stapleton was too big, and far too obvious. No offence to Richard E Grant, but his manic, nervy, edgy style was completely wrong from the beginning. You are expected to believe that another claimant to the Baskerville title and lands would have hidden in plain view in such a flamboyantly obvious manner, and not have aroused people's suspicions? It then got worse. The violent end for "Miss" Stapleton was unpleasant, not in the book, and totally unnecessary. The hound was dreadful, some of the worst CGI I have ever seen. The end of the story was changed for no apparent reason, and was not an improvement. The blood and gore, merely gratuitous; Holmes floundering in the bog, and Dr Watson's sharp shooting act finally killing Stapleton totally missed the point of the true ending.