Well, do you want to know one of the good reasons I don't use Firefox? It's not compatible with 20%+ of the websites and scripts out there. Internet Explorer (and by inheritance, Avant Browser) on the other hand is completely compatible with 99.9% of the websites and scripts on the internet. The 0.1% that Internet Explorer cannot understand is made specifically for a different browser (such as Firefox or Opera) and is usually there because a Firefox/Opera lover wanted vengeance on those who openly admit Internet Explorer is not only more compatible, but now it's actually safer.
Just one good reason... There's many more. By the by, it's Avant, not Ad
vant. Notice the spelling in the link: http://www.avantbrowser.com/