Great watch, would watch again, and can recommend.
If you're accepting or even intrigued by the case of Jack the Ripper, then this should be a great murder mystery for you.
Johnny Depp, opinions aside, does confused, drug-addicted, and detective all well. Heather Graham is able to emote and elevate her role wonderfully, despite it basically being a damsel role.
Almost everyone else is old British guy, and it really feels like the complex mystery and drip-fed information investigation is really what makes the movie stand out.
Fortunately, despite the movie still being somewhat gruesome, it's not a complete gore-fest, so there is very little to distract from the investigation aspect of the movie except for a ill-found romantic entanglement.