Just downloaded Internet Explorer 11 to check the browser. IE 11 is in developer version but working without any problem. Yes, it has been warned that issue can come and you may need to update browser frequently. Update will come frequently for sure as this is still in development. Download file size is 54.3 MB.
A) One thing I have noticed is that font is looking too crisp in Facebook and Twitter. I checked few more sites (http://readwrite.com/) and there also it is looking different than Firefox.
Here is a snapshot from readWrite.com:
B) Another thing to notice is that on the TaskBar, number of open IE was the number of Tab open in a IE 11 instance.
C) Developer tool works like Firebug. Cool!
E) Do not Track Option - Stopping Websites snooping users activities.
F) IE 11 has new user agent signature.
G) IE 11 has adopted web standards for DOM etc therefore now it will work like Firefox and Chrome etc. No need to write separate code for IE alone.