Avant is great; FF is faster sometimes; both are necessary
On my system, (which is overdue for a complete re-install of XP pro and all other programs), IE is so damaged that, if I click on a link in another browser which insists on calling IE, I get so much junk on my screen so fast, that I must use Task Manager to shut down every browser instance I can find, and re-start Avant or Firefox, depending on which I am using. It is very aggravating! I have scanned IE with every piece of software I can dig up, and have tried editing the registry line by line, manually, but I cannot clean enough out of IE to make it useable. The interesting thing is, I CAN use Avant Browser, which uses that same IE program, with no trouble at all, as long as I don't allow IE to be called. That is an indication to me of how well Avant is programmed; it can even use a damaged version of IE and prevent it from doing anything wrong!
I use both Avant Browser (which is very friendly and easy, especially when I "surf" a lot) and FireFox, depending on what I am doing. If I wish to, for example, "bounce around" on ebay, clicking on links to examine products, read messages, etc., I prefer FireFox because it seems to re-draw much faster when I use the "BACK" command to return to a page from which I followed a link; it also seems to receive and draw a page faster than AB does, overall. However, FF is more like using a clutch and stick transmission, whereas, AB is more like using an automatic transmission. Each has its place.
I am not sure if I could make a list of strengths, weaknesses, features, etc., which shows one to be better than the other, but, I would not wish to give up one of these two excellent browsers and use only one of them for everything. Since they are both "free", I don't need to worry about using them both. However, if I had to make that kind of choice, I believe I would go with FireFox. The superior performance ultimately would win out in my case; sometimes, FF will load and disply two or three pages by the time AB or IE can do just one page, in my non-scientific, non-controlled, non-standard, subjective testing experience.
I have been using the Internet since Mosaic first came out, so I am fairly competent. I am also an electrical engineer and sometimes programmer; using a computer is as easy for me as scratching my head when I don't know what is going on with my latest creation. My wife, on the other hand, was a complete "newbie" when I recently set her up on a laptop. She began using IE "because it was there", but, when (sometimes extremely offensive pornographic) junk started popping up on the screen so much that she could not use the Internet, I installed AB and FF on her system. She tends to use AB because it is more like IE, and she is familiar with that. She is not as demanding as I am, and does not care about the relatively small performance increase of FF which I find important; mostly, she just wants to use the computer for simple Internet access and does not "surf" much. Anything which allows her to get the job done without learning new skills or attitudes, etc., will be her preference every time; she is totally opposite to my way of doing things, thank goodness!
I don't believe it is necessary to have the available browsers "fight it out" until only the superior browser survives; that mentality, unfortunately, has been promoted so much by MSOFT's practices that we sometimes forget that it is good for us to have more than one program to choose from for a given application. I would hate to see ANY of the competing browsers so dominate the market that the others would be forced out, such as happened a few years ago between MS and Netscape! viva la difference (sp?)
As has already been mentioned, it is perhaps good to have IE out there as the main target for the nut cases who write virus programs to focus on; maybe it will keep them busy so they won't attack the other browsers with as much vigor as they have shown in their IE attacks so far.
Two browsers are better than one! (Or three or four or five are perhaps even better!) Any browser which is not good for an acceptable number of people simply won't get used, and it will "go away" if the authors of it do not change it until it suits the needs of their target audience. Isn't that the way it is supposed to work? Seems pretty good to me.
But of course, it is also good to have forums such as this, and to have debate, and to have so many knowledgeable people share their experiences with the rest of us, so we can make more intelligent choices. Or at least, so we can avoid looming problems before they damage our data and do us in.