Not the best game, but far from the worst. Of course, it helps to be a fan of the genre.
The major downside of this game is the same thing as in it's predecessors... It's slow game-play. People who are expecting a fast-paced action-packed sword fest will be sorely disappointed. Even running seems slower than walking in most other first person games. Of course, the fact that this game has no loading time whatsoever between different areas does make up for the slow game-play, though it only make up a little bit.
The Ancient City is by no means an action game, though there is a fair amount of action to be had. The game revolves more around tactics and problem-solving. That, and the aforementioned slow game-play, gives the game a more realistic feel to it, which might appeal to some gamers.
All in all, it's a good game. Especially if you enjoy this type of game.