I went to Bennigan's in Seoul Thursday night. It looks just like the ones in the US. I am not sure about the menu cause it's been so long since I have eaten at Bennigans I have no idea what's on the menu at the ones in the US.
I have also been to Outback Steakhouse last October when I was visiting. It's about the same at the US. They have TGI Friday's but I have not been there.
Some American fast food restaurants I have seen here are McDonald's of course, Burger King, and KFC. I wish there was Wendy's here.