I've been doing a ton of the side-quests and trying to complete all the collectibles, but I'm not trying to complete every quest. That said, I'm 12 hours into the game, I think around level 25, and something just happened that seems to suggest that I have only just scratched the surface. So awesome...

I love this game. The characters are great, the game is fun to play, the world feels massive, you're never left without something to do, and the story is genuinely interesting. Also, you're constantly getting loot, you get exploration xp and the quick-travel system makes running back to town to sell some of the crap you picked up completely effortless.