Dishonored and Thief (I think others were referring to the new one but either way) are both sneak/grab/stab games. They're not identical but they're in the same genre and sub-genre.
I tried Dishonored twice too. The first time I didn't get into it but the second time I got hooked and very much enjoyed it so Dishonored II is one to look out for. How good are Dishonored's expansion packs?