Another important difference thus far unmentioned is that IE is a browser for a single platform, and Microsoft traditionally has not done a good job in creating

Another important difference thus far unmentioned is that IE is a browser for a single platform, and Microsoft traditionally has not done a good job in creating IE features in a cross-platform way. (I'm thinking of ActiveX specifically here.) If a feature is led by Chrome, Firefox, or Opera you know that any native platform hooks have been designed thoughtfully to work nicely across at least the 3 major desktop platforms.