I just finished it, and I'm pretty satisfied with it.
Like Far Cry 2 I can't find a single reason why they made it open world though. Pretty much every demotivating, laborious piece of content seems to be there just so they can justify having two big open islands, and for me that makes it less of a game.
It has some amazing story elements, and a lot of great characters. Guys like Sam and Earnhardt are legendary in my book, and some of those dream sequences really blew me away. It's such a shame that they're padded with all that mediocrity.
I skipped most of the hunting and sidequests, and I only collected enough stuff to unlock the weapons. Outposts were decent enough, but for a game that openly states that repetition is the definition of insanity, it sure as hell packed a lot of repetitive tasks.
I'm thinking that if it had been a linear shooter, and had room to focus on more of those amazing cinematic sequences, rather than trying to fill out two unnecessary pieces of land, it would've been game of the year material for me.