It turns out that it looks ugly -- for a while, and then you get used to it. (Note that this picture is likely 20% larger on your screen than it is on my laptop's screen.)
But I've also discovered that since it's fashionable to design in ems and not px, there are tons of broken websites that do the layout in pixels and the fonts in ems. This means that the text just gets chopped off. I wish they would just make a clickable image map instead, because that's what they really wanted in the first place.