For me as a great Dishonored, Hitman, Deus Ex and Splinter Cell fan, this game was an absolute treat. The different approaches, the atmosphere of the game world, the game play: everything fits perfectly! However, unlike all listed above playing this game is by far the least suitable for the impatient and especially brachial previous people. So if you really stands on pure stealth with velvet patience and a few moments of frustration: clear Best Buy!
As one of the most enjoyable game elements the strong first-person point of view has been the way for me proved, which was nor ever used in any single game earlier as well. In the above-mentioned games Dishonored and Deus Ex, for example to drawers and doors open automatically in interaction while still himself has his hands on the weapon. In Thief Garrett really reaching for the door and makes it on. That makes for a tremendously deep atmosphere.