I'm a long time user of Opera.
Always surprised why it is very underrated.<p>Just for the record :
* Opera is and was the fastest browser on limited memory/cpu machines
* Opera is the most user friendly browser, it has always been so. (tabs, sync, speed dials, quick preferences, full zoom, email client, irc, skins, notes, downloader (btw, opera has the best "builtin" browser downloader ever, you can actually open files while downloading), history search (yes, opera's history search is the best), debugger and countless of small other useful details & features)<p>This browser is simply a treasure, yes I have tested every other browser and I keep a copy of FF with a bunch of plugins.
More details from the Opera developer blog can be found here: <a href="http://my.opera.com/desktopteam/blog/2009/12/22/from-all-of-us-to-all-of-you" rel="nofollow">http://my.opera.com/desktopteam/blog/2009/12/22/from-all-of-...</a>
Also, Opera is of course the malware writer's choice du jour because it's tighter than a pigeon's chuff.<p>Quite funny seeing the recent Firefox menu button being a complete rip off of the leaked Opera 10.5 build.
The versioning nomenclature seems somewhat chaotic... here it says 10.5 and their current version is 10.10 and on the linked page they refer to 10.1 and also talk about 10.50.
I guess that 10.10 == 10.1 and 10.5 == 10.50 but it is a bit confusing...<p>Oh, and the download crashes with SIGBUS on my MacPro running 10.6 :(
More details on the javascript vm: <a href="http://my.opera.com/core/blog/2009/02/04/carakan" rel="nofollow">http://my.opera.com/core/blog/2009/02/04/carakan</a><p>From my somewhat limited knowledge of such, it seems like they took a fairly similar route as the Webkit guys. (Register based, etc..)
Thought I'd give this a try since I never gave Opera much of a chance, and I'm usually very tolerant of alpha/betas as long as they mostly work.<p>Lasted about half an hour - Google Reader doesn't seem to work right, and GMail also stopped responding after a while.
If the default browser in OS X was as crappy as the default on Windows, I'd now be using Opera, with Chrome in a really close second.<p>Firefox has a million extensions, but speed matters more to me.
Windows 7 user here. It's been a long time since I tried out Opera properly last time, but I have to say this new release is snappy, smooth and very, very clean. And unlike Chrome it actually tries to mimick the native UI conventions without getting boring.<p>And as other's have mentioned, the Windows 7 add-on features are a nice bonus.<p>I like this very much.