See, the thing I'm liking about editors—and this is coming from a Typography/Graphic Design instructor—is how they keep using em dashes properly.
I've received two emails from editors over the past two days, and both included the correct use of em dashes. The one I got today used two em-dashes and a hyphen properly in the same sentence! And on top of that, both editors used only one space after every period.
Oh, yeah. They get it.
Call me anal, but I'm thinking those are the people I want working on my books.