People in my office (including me) move around with their MBPs pretty frequently. I know saying "other than the keyboard, they seem to be pretty well built" is the tech equivalent of "other than that, Mrs. Lincoln, how was the show," but I've never had any issue with waking up from sleep, or display issues when I disconnect the external monitor, whether or not the laptop lid is closed at the time. (I generally run with the lid closed when I'm at my desk.)