"Why don't you go and read a few novels instead? (Moby Dick would be a nice start.)" My gamer friends like to ridicule my fondness for PS:T. Yet, here I go, spending way too much time on countless lines of dialogue, butchering cranium rats and strolling through shadowy dungeons.
Shadows, shadows... What I like about PS:T, and what keeps me playing, is that it's different. A lot different. This is no sweet fairytale fantasy world, this is real agony. People suffer here. The visuals only hint at the gore that awaits the player in the long dialogues.
Sigil, the city of doors, is full of filth - and even the knights in shining armor appear somehow tainted. What is good - what is evil? Hard to tell in PS:T.
PS:T is unconventional in many ways: You start with two characters only, and build a party from people you find in the streets. Your alignment changes with your actions and words in the game. You fall in love with party members. You cannot die - you merely wake up someplace else and feel awful.
My only real complaint with PS:T is the long and frequent load times. You better enjoy this with lots of RAM and a huge full install on your hard disk.
Other than that - highly recommended.