This recently released DLC looks promising to me but only if you enjoyed playing the original in stealthier mode I guess (as it's a bit short if you go in guns blazing).
Enjoyed Dishonerd but didn't feel compelled to go back in and replay levels to try and gain the missing achievements or Ghost it/whatnot. But I may well cough up the £7.99 asking price and get this from Steam as it's different enough to maybe make it worthwhile.
Couldn't say I enjoyed the DLC for Skyrim overly much. The Vampire one was good but the Dragonborn one was really poor in comparison and the asking price was a lot higher too. So, The Knife of Dunwall looks like much better value already then.
Here's a review. Anyone else tempted?