As my primary browser I use Firefox — On OS X my primary browser used to be Safari but since my switch to using XP primarily that hasn’t really been an option, hence using Firefox. Occasionally I will use Opera web browser to check the appearance of something or for other reasons, and one of the things I noticed with Opera is that it had automatic session-saving. That is to say, if I were coding something and had multiple reference windows open in Opera, I could close Opera without a second thought and when I reopened Opera it would automatically reload all the pages I had open and restore them to their previous state. Needless to say this is a really helpful feature when you have to close your browser, whether that’s just to get rid of distractions or to free up memory. In Firefox I would tend to go for a week or more without closing my browser for the simple fact that closing my browser would lose all of the tabs I had opened up.
For a time Opera became my primary browser for the web and particularly for doing programming and other work. There were some things I missed though, and even attempting to make Opera work for me as my primary browser, I found myself opening Firefox on a daily basis. I decided that if I couldn’t use Opera as my primary browser I should look into what made me love it so much in the first place: session saving. One Google search away and I had found what I was looking for: Session Manager. I downloaded it, restarted, and so it began. I’ve been using Session Manager for about two weeks now and it’s hard to imagine web-browsing without it. Currently I’ve got twenty tabs open in Firefox — Usually that would mean that I’d be forced to have Firefox open until I either: (a) copied and pasted all the relevant URLs to a text file for later use, or (b) finished all of the tasks or ideas represented by those various tabs. Either way, it’s likely that the browser would be open for at least a week. With Session Manager I can close the window and enter into that nirvana of browser-less information-deprivation without the apprehension that I’ll close something that’ll take me an hour to find again.
I’ve been using opera as my everyday use browser since version 5.x. The native mouse gestures are awesome, and while I occassionally need to open an IE or Firefox browser to do something, those instances have become less and less frequent as Opera updates their browsers (the current 9.x versions are the best yet). Mouse gestures certainly qualify as a tool that changed my life. Firefox has mouse gestures (as an extension), but they’re not as smooth as Opera’s.
The session saving is also cool, as is that little trashcan that saves all the windows you closed in case you accidentally closed one (something that happens easily when using mouse gestures).
Still, I can see why most people go for Firefox. It’s got some advantages over opera (and both are way better than IE), including the massive library of extensions and plugins (Opera really needs to do a better job of that), but not enough that I’d consider switching myself.