Forget about IE. I was amazed that you can get free testing licenses for all versions of Windows. And being able to legally run them on my Linux via VirtualBox.
I only have one OEM Windows XP, but need to test IE6-11. Sice there is not way to run them at the same time, I always had to ask my friends to test. Finally I can do it myself.
"Modern" IE that doesn't support WebRTC, HSTS, and the most behind in supporting HTML5 features [1]. If that's "modern", I'd hate to see how their "non-modern" products look.
Not many sites use HSTS yet. IE says they'll support it in the next version anyway. For everything else you mentioned, they're right on par with Safari, which is not bad.
I only have one OEM Windows XP, but need to test IE6-11. Sice there is not way to run them at the same time, I always had to ask my friends to test. Finally I can do it myself.