I've been playing the PS3 version since last Friday, and it definitely has its share of bugs. I've gotten stuck inside a tree, I've jumped straight up high into air and fell to my death, the sound is buggy at times during the cinematics, and sometimes the characters lips don't move during the cinematics.
That being said, I've played about 20 hours, and I'm only up to sequence 7, I've pretty much been roaming around, and it's been great. The sheer size and different elevations of the frontier are amazing. Oh yeah, the rope dart is badass too.