I'd recommend the game. It's pretty fun and the boss fights are pretty weird, overall it's a fun time. The reason I first was interested in it was because R.A. Salvatore was hired to write the mythology and I'm a big fan of his books, but the more I looked into it, the more I excited I got.
But as to side quests....They aren't bad. The Travelers sidequests were the ones that i fealt least compelled to do, and I haven't done any of the Scholia Arcana quests because I never really found them the few times I played all the way through. The game came out around the same time as another I bought, so I was split between the two games, but it's still worth buying, or at least renting or borrowing.