Why are you repeating what I said? Of course they don't. It's a made up thing by Microsoft. No modern browser would use them. Of course not. IE8 is not a modern browser. No one should use IE. It's inept and incompetent and an embarrassment to Microsoft. All modern browsers can run parts of HTML5 but not IE.
Never heard of Avant before coming across this thread. I'd personally never use a browser that doesn't have a website of its own and is only available for download from software download sites for security reasons. To be on the safe side, I recommend using well known browsers that have been out there for a while, such as Opera for instance. In fact, I've been using Opera for at least two years and I think it's the best browser I've used so far, better and more stable than Firefox.
When it comes to the modern browsers (everything except IE), it comes down to personal preference. I use FF for dev work but am more likely to surf with Chrome. I like Opera but I don't need to be using three browsers.
Surprised most people here use Firefox over anything else. I was a dedicated user until the random crashes and the inability to close certain tabs became too much. Google Chrome for me now