I have had a spurt of web programming and web design work as of late. Along with a fresh new openSUSE install, this has driven me to give Opera 9 a try. I've been using it as my primary browser for a couple of weeks now leading me to decide to pen a few words on this venerable piece of software.
Opera is the Apple of web browsers. It is probably the prettiest browser you can use. I personally love the way it renders. Everything is very smooth, particularly the fonts. It isn't even something I can really put my finger on, so much as it is just the general experience. Also like Apple, Opera is an "all-in-one", no configuration, relatively little customization. If you like it? Great. If you don't, tough. The package IS the product. From Bittorrents, to adblockers, just about everything you would normally download an extension for in Firefox comes packaged right into Opera. Whether you consider this good or bad is an entirely subjective matter.
On the whole, I find Opera to be pretty much on par with Firefox. There were a few things that I did like better. Not really technical issues, just preferences. I liked the way Opera automatically alphabetizes the bookmark listings. I keep a lot of bookmarks (which makes the Opera/Firefox/Netscape parlance of bookmark more accurate for me than that of Internet Explorer), so this makes it a lot easier to dig up older resources. As crazy as this sounds, another thing I liked were the JavaScript errors, which mattered because, as I said, I was developing a web app.
I did have only complaint: Opera crashed on me--a lot. Programs crash, it, to some degree, is a way of life. Nothing is perfect and, sometimes, it really is safer just to die, but Opera has given me more random crashes than I care to think about. At least session saving worked well.
In conclusion, draw your own. These are my experiences. Download Opera and tell me yours!