As to chain restuarants, I've eaten in some Applebees in the Southern US and found them decent.
As to other restuarants, there is a very good restuarant in Portland, Maine (USA) called Saigon Thinh Thanh. It has lovely Vietnamese food.
There is also a good Vietnamese restuarant somewhere between Portland and Hartford, Conn. (both USA), called Phu 501.
In Rockland, Maine (USA again) there are two nice small restuarants I eat at with my mom a lot. One is called Cafe Miranda and the other is called Primo.