I played a Study in Steampunk after I had spent several months rereading the original Sherlock Holmes stories. I had discovered that Sherlock was very different from modern versions: no "elementary, dear Watson", a lot of strength and physical activity, minimal pipe use, etc.
So when I started this game as John Watson and my friend said 'the game's afoot', I rolled my eyes. I couldn't get into the storyline about dueling empires with mechs and soul-draining powers.
But I tried again two more times, and on the third time, it stuck. I think the first chapter just wasn't as strong as the later ones; the game began offering really intriguing role-playing choices, and ended up setting up several compelling life-and-death situations that were effective.
The decisions were effective, I believe, because the game is just so long. It has a lot of minor faults I would usually take off points for (like obvious choices between being good/being evil or by-the-numbers genre scenes), but the author clearly has a deep understanding of long-form game design that just makes it fun.
I enjoyed it more once I realized that it wasn't really a Sherlock Holmes knock-off; it was really the author's own vision, with some Sherlock-related elements. The author cites Dracula and Jack the Ripper as inspirations, too, and these are almost stronger; supernatural life-draining is one of the main game topics. It also suggests Jekyll and Hyde as an influence, but I saw nothing of this in my playthrough.
This game is effective because of how long it is, and is definitely worth its price.