I have an XPS 2-in-1 and I open to 180 degrees sometimes when laying down and using the touchscreen. It sometimes works in economy seats as you can rest the laptop on your lap and then the screen is kind of like a seatback IFE. But if you opened it flat on your lap, the screen can't open that far because of the restrictions of the seat in front of you. I also will put it in "tent mode" e.g. over 270 degrees open and the screen upside down on the tray table to watch a movie.
About the only thing I don't do much is use it as a tablet as its kind of heavy, even though I have the Dell pen for it.
