Works as described.

The only downside using this extension is that it does open a separate IE browser window and doesn't run an IE engine inside your Firefox tab like other extensions do.

If you're having issues, make sure you've set up the extension's options:

≡ > Add-ons > Extensions > IE View WE > Options

Path to Internet Explorer = C:\Program Files\Internet Explorer\iexplore.exe

Website to be opened by IE always = http://example.com/*