First off, anyone who does not like reading, or isn't very good at reading, this is not the game for you. As it says on the back of the box "To fully enjoy this game you will require basic reading ability".
If you like solving puzzles, reading and a little bit of role-play, then this is the game for you - definitely.
Although the characters are quite linear and some "complex" animation is disappointingly simplified to a somewhat pathetic extent (eg, when someone goes through a door, you see the door opening a little, and you see the character going through it either fade in or out).
However, the game makes up for it by expressive character animation (although they use the same selection of character animations throughout the game - but this is expected) and charming dialogue. The backgrounds are beautiful, and carefully done.
You can also "interact" a little in the dialogue, because in some parts of certain conversations, you can choose what answer Ashley (the character you play as) says. And these do have a little impact on the game.
Some of the puzzles are very easily solved, a few may require some thought, and others will almost certainly require for you to go online and look for a walk-through - unless you're very good at solving puzzles.
One of the things you will definitely get stuck on for a good while (at least) is in the clock tower (unless you're a total smarty-pants =P).
The first time I played it, it provided me with just over 22 hours worth of game-play. The second time I played it, it took me nearly 14 hours.