To second what Navarr said, I don't really see IE issues these days unless it's on a site that needs to support versions prior to IE9. As often as not, issues in modern IE are due to developers writing code that targets only a single vendor-prefixed version of an API instead of supporting standards, which makes IE look deficient (instead of that sloppy developer) even when it has good support for the APIs that a site uses.
To name just one thing that IE still doesn't support: setting the download attribute on a link. Neither does Safari.
This makes it very clumsy/impossible to write real web apps that need to save to the local file system. The scenario is generating a document client-side using JavaScript. Now you want to let the user save it. In Firefox, Chrome, Opera, and no doubt others, this isn't a problem. Just set the download attribute on the link to the file name you want to use.
