Planescape is a much better story than game so it's more a question of just how interesting do you think the plot is. Interesting enough to plow through some questionable game design?
If you do plan on going through with it then let me tell you that it's a very unique and quite satisfying story. Also from a gameplay perspective two things will help you out - be a Mage and dump all your points into intelligence. That and talk to everyone constantly - and be prepared that they'll have plenty to tell you. Being a Mage somewhat trivializes combat later on as you become insanely powerful and having a ton of intelligence unlocks more dialog options which help to flesh out the story and learn more about your companions.