I haven’t heard of FireExplorer in particular, but trolling around the internet shows a number of dissatisfied customers…is it a hacked-together program? Who can tell? If you’re a fan of FireFox, you should probably stick with it, but for those times you need to use IE to view a specific page, if you don’t feel like loading up the full version of IE, you might want to take a look at the IETab extension (http://ietab.mozdev.org/) which allows you to run IE pages from right within a tab in FireFox.