I use Opera because it's one of the few pieces of software I've found that is truly *intelligently* designed. Not just well-designed, nicely designed, functionally designed, etc. But truly intelligently designed, IMO.
One immediate example that comes to mind is the incredibly simple but highly effective and useful pop-down thingamajig that shows up when you click on the address bar. Normally I would have a "home" button in my toolbar, taking up space, but it's nicely included in this little drop-down thing. I don't use "home" all *that* often, especially with Opera's built-in address bar searches (another smart feature), but when I do I want it to be quick - faster than a menu, though it doesn't necessarily need a dedicated button. So this works perfectly. It also gives you access to common search functions, most-used sites, etc.
Being able to search functionally with keywords ("g donation coder" typed into the address bar will search Google for "donation coder") is another great example of smart design. Yes, there are plugins for Firefox that do this, but Opera does it natively and very well.
Built-in right-click translation and search is another great, smart thing. Again you can get a FF extension for this, and granted the FF extension will probably be more customizable, but I've never had need for a feature like that isn't covered in what's already in Opera. That IMO is because Opera is, again, *designed intelligently*.
Another example? The history/undo/recently closed pages functionality is *fantastic*. Not only does it allow you to retrieve recently closed pages, but it actually remembers the entire session from when you opened that tab in the first place, *and* its position in the tab order, so you can re-open the tab and actually step backward through how you got to a given page. This may sound kind of extraneous but I've actually found it *tremendously* useful.
One thing that some people might not like but that I think is also cool is that it remembers your *position* on web pages, through reloads and browser sessions. So if I am at the bottom of a forum thread and want to see if there are new posts I simply refresh and it *keeps be at the bottom*. So I don't have to scroll all the way down on a long forum thread. Once I noticed this I immediately liked it. It's even cooler when for example you're reading a long article and have to close your browser. When you open it back up again not only is the page you were reading still there, but the *position* you were at is also there. Intelligent design.
As for basic features, which I was surprised to find FF lacking when I decided to migrate from Avant, there is the full-featured Tab support and the automatic session save and retrieve. Opera, like Avant (and unlike a default FF install) is excellent at maintaining your web browsing session and even your place in browsing a web page through a close and reopen cycle. And if you crash (rare) or have a power outtage, etc. (more common
), Opera still saves your session and all open pages.
Bookmarking is very well handled for the most part, once you get used to not being able to edit directly from the bookmark menu (this *is* a feature I would like, but Opera's full-featured Bookmark editor makes it less necessary). You can sort just about any way you want on many different criteria. It remembers the last bookmark folder you used (unlike IE) so if you want to bookmark many similar sites (as I often do), the process is very quick.
The Magic Wand feature is also something I love. The best implementation of in-browser password saving I've seen - provided you trust its security (I do - I trusted IE even, so that shows how little I am worried about it, lol).
It is also, as many people said, very fast. Going back and forth between pages is quick, going backward in a web browse session is *lightning* fast due to good caching, and the only problem I ever have with that is if I really want a page to reload I have to explicitly do so. But I can also appreciate this as a feature because it doesn't reload unless I *ask* it to.
I find the toolbar customization and other customization functionality to actually be pretty awesome as compared to FF and others, but I will say it is slightly unobvious at first how exactly to use it. Once you get the simple approach it's very easy and fast and powerful.
There are a lot of Opera features I know I don't really utilize, either. Like note taking, which is pretty cool (although I'd want it to be more robust before I got into it - like being able to save website clips). The e-mail app is also supposed to be decent.
I will also say I'm a bit disappointed in the new features they're bringing in Opera 9. Bittorrent for example seems completely extraneous to me. I already have a fantastic Bittorrent client under 200kb that runs with incredible efficiency and has just about every needed feature - uTorrent
. But I guess some people wanted it. *shrug* I also don't know what's particularly cool about "widgets", but hopfefully someone will show some cool purposes for it soon. I would have liked to see them implement even more customization functions and perhaps even some kind of easier plugin system (Opera *does* support Netscape API plugins, which is a little-known fact, so more plugins *could* be made for it, it's just not as easy as with FF), and there are a few little niggles I have too that I hope are addressed (my bad for never having reported them). But for the most part Opera 8.53 is great for me already. By far the best browser I've found. I really never find myself missing FF or Avant these days. I could go on and I know I'll remember some Opera features I love that I haven't covered yet, but this is good for now.