It works the way I like. Why is that hard to understand?
"Opera gets a bad rap, but most people honestly haven't tried it for a month."
Couldn't get along with it for a full month. I've never called it a bad browser, though its fanbase are even more annoying than Apple's. The simple reason I use FF is that it works the way I want it to. I'm a developer, and as far as I'm concerned, Firefox has the most consistently accurate rendering of all the browsers. It's also a lot faster in recent versions, and once you start building on top of its base functionality, the plugins I have installed have made it invaluable as a development tool.
For example, just the other day I discovered Poster, which is a tool for simulating POST/GET requests to APIs. Sure, there are other browsers and other add-ons which make this possible, but it's just such a well-made, nicely laid out and straightforward add-on that I've now installed it on every machine.
Being able to customise FF to *exactly* how I want it is what makes it perfect for what I do. My downloads open in a tab because I want them to, I've changed some of the menus, Flash only plays when I want it to, I never see ads, and I can literally edit pages in place, enable/disable their various features, etc. Firebug is so awesome that other browsers have almost copy-pasted it into their own interfaces, and extending it for Drupal/Moodle/PHP is just damned handy.
The awesome bar is also an absolute killer. It works better than anything I've used in any other browser, Chrome and Opera included. I almost never have to go directly into bookmarks or recent history, because it's just so good at finding what I'm looking for.
The same thing has happened with my phone. I used to use Opera Mobile, but since FF mobile got its act together and sped up a bit, I now use it exclusively. It syncs, just like Opera, but it brings with it the same features that I love from the desktop version, like the awesome bar, and for fullscreen browsing it's the best damn mobile browser out there. It had a rocky start, but it's gotten really quite good.
Opera's not bad, and if it wasn't for the spyware Chrome would be alright, but FF is just...better for me. Note: for me. You want to use Opera, that's dandy, but what you see in it isn't necessarily what's useful or right for other users.
Seriously though, Opera's fanbase don't help. You don't see roving bands of Chrome users posting on every browser article and downvoting anyone that speaks out against it, do you?