IGN gave it 9
http://www.ign.com/articles/2012/09/14/borderlands-2-review
Gamespot gave it 8.5
http://asia.gamespot.com/borderlands-2/reviews/borderlands-2-review-6396650/
Based from the reviews, it's worth it!
Based from the reviews, it's worth it!
But IGN and Gamespot are quite shunned by the community because of their reviews. (COD reviews)
I suggest checking out PC Gamer, RockPaperShotgun, forums (TPC) and even friends (that have your same taste in gaming) for reviews.
Of course, this is subjective so to each his own.