Well, not really but they’re probably more right than they know.
Ya see, in 1998 Netscape released the source code to their browser to the world. They did this to prevent Microsoft from owning the Web utterly and mutating it into something only MSIE would be able to use. A bunch of volunteers sprung up around this source code to build an open-source browser. They called it Mozilla, after the name of one of the early prececessors to Netscape. (As it turns out, the Mozilla Project had to toss out all of the Netscape code and start from scratch, because the code they got was badly-written. But there are definite links between Mozilla and Netscape.)
Netscape won this gambit: They prevented Microsoft from locking up the Web and ensured a market for Netscape server software, their real moneymaker. Meanwhile, they pretty much got out of the business of designing their own browser: Later versions of the Netscape browser would be rebranded versions of Mozilla. So for a while, you could reasonably say that Netscape version n was really Mozilla version y.
Netscape was bought out by AOL and the Netscape browser formed the basis of the AOL browser for a while, until AOL decided to go with a rebranded MSIE instead. Meanwhile, the Mozilla Project was attracting some detractors: Mozilla had become a rather heavyweight piece of code, and it still wasn’t considered `finished’. Plus, it was designed as a full Web development tool, including its own HTML editor and email client in addition to the Web browser. People wanted something smaller, simpler, and better-behaved.
Enter Firefox. It was designed as a simple Web browser built up around the Gecko rendering engine (later to serve as the basis for a lot of other browsers, Safari among them IIRC) and supporting a simple way to write extensions in a portable, high-level language called XUL (pronounced Zuul, as in “There is no Dana, only XUL.”). This wasn’t a complete break with the Mozilla Project – after all, the browser calls itself ‘Mozilla Firefox’ in its titlebar – but it was a new development in the codebase. And it would cause a sea change in how people saw non-MSIE browsers. In a relatively short while, it would be seriously eating into MSIE’s marketshare and getting the attention of people who would otherwise never have considered jumping the All-Microsoft ship.
I do the same thing. Slashdot loads correctly in Konq, and the KDE toolbar RSS crawler only opens pages in Konq.
Plus, FF and Konq handle tabs a bit differently: FF makes them all visible at once, eventually making it impossible to read the text. Konq scrolls the tab bar so each tab maintains a constant size.
However, FF is a lot more configurable than Konq, and it’s more willing to open tabs in the background.
Opera is nice enough, but it doesn’t have near as many extensions and it really isn’t different enough from Konq or FF to make me switch back now. Being able to finely control page rendering is nice, though.