I would most certainly buy it. I'm glad I did. These days, you can find it for around $20 or so. I've played through BG2 and Torment (never have played BG1) after a 10 year hiatus from playing computer games. Years ago, I started to play a game called Advanced Dungeons and Dragons, back in the days when it was a new game system from TSR. I remember the feel of it. There weren't any kits, full plate armor, and bards were a curious combination of a fighter and a thief (you were actually multi-classed).
Somehow, IWD managed to bring the feel of that game back to me. I like everything about it, from the music to the storyline. True, it's certainly linear, but it sure is alot of fun to play. If you simply experience what it has to offer, you'll find yourself liking it more and more. I enjoyed BG2 thoroughly, but since it's a much larger game, I don't bother comparing the two. Besides, there was something about playing a straight-up paladin that reminded me of the old days...