IE 11 is the most stable and secure version out there. I use it on both Windows 7 and 8.1 without any problems. I think it is much faster than IE 8 and 9. It is much more secure than all previous versions. However, it does not work exactly the same on Windows 7 and Windows 8.
As for all of the naysayers, I use Chrome as well, and don’t find it to work any better on Windows 7 than IE 11. Keep in mind I do not run it with any funky plugins or toolbars. Also the new MS Browser (Edge) will be out in July with windows 10, I’m not sure if it will be backward compatible with Windows 7 or 8.
I think they are ditching silverlight/activex. That means there are sites that will have broken features. I see it with Chrome on a lot of intranet sites.
There probably is some money to be made fixing those clunky sites. :-)