I saw the news that the alpha of Opera 10 was released. Among the hype was that Opera 10 was pixel perfect and scored 100 out of 100 on the Acid 3 test. Intrigued, I grabbed the .deb, installed, and gave it a test spin. Unfortunately, even though it scores 100/100, and is pixel perfect, the rendering is not smooth. Per the qualifications to pass the Acid 3 test:
To pass the test, a browser must use its default settings, the animation has to be smooth, the score has to end on 100/100, and the final page has to look exactly, pixel for pixel, like this reference rendering.
Grab a copy, and see if it is smooth for you. It certainly isn't for me. It pauses briefly between 18 and 26. This might be splitting hairs- whatever. However, I have to say that I'm incredibly impressed with the browser overall. It's incredibly fast rendering pages, it finally comes with an auto-update feature including daily snapshots, rewritten regular expression engine adding more speed, enhanced mail features, better transparency support for widgets on Linux/Unix, and a number of other features. Of course, Opera is among the standards-compliant web browsers.
It might be proprietary software, but in my opinion, it's ahead of Mozilla Firefox in terms of speed and features. What impresses me the most, however, is the size of the binary. It's considerably smaller than Firefox, yet it boasts better stability, better features and faster rendering. I haven't looked at the code base for either of them, but I would really like to see some of this code goodness make it into Firefox. Maybe Firefox should do a code cleanup for a major release?