What could be a great place to work is let down by a bullying culture. Lots of CYA going on to hide people's incompetence, lots of brown nosing, favouritism and cliques.
Working with colleagues in the US is not a great experience. All take and no give, some very archaic and backwards thinking and a general sense of "we're American, therefore we must be right".
But really it's the back stabbing, duplicity and bullying that will get you in the end. People openly lying to your face, backtracking on decisions you've agreed with them and then denying any knowledge of what you agreed in the first place. People who being nice to your face, then stabbing you in the back at the first opportunity and so on. Eventually it wears you down and you realise that underneath the veneer, it's not a very nice place to work at all...