Both Opera and WebKit have worked hard to resolve their bugs that were exploited by Acid3 and both have now released public builds that pass the test reasonably well.
Opera has released a copy of WinGogi (for Windows) and LinGogi (for Linux) that passes the test. Unfortunately, there is no Gogi for Mac. Gogi is an internal build using the latest, cross platform rendering engine, but which lacks the normal desktop user interface. The WebKit team has also announced their success a few days ago.
It should be noted that these changes are unlikely to be incorporated into the next upcoming release of Opera, which should be coming out some time in the near future.
You should be aware that two of the tests (test 26 and 69) are performance test, which may trigger a slight pause. These may be affected by the computer’s hardware and internet connection speed. This is actually a fairly subjective part of the test. There is no clear fail condition for it, but if a browser is significantly slower in comparison with others, it’s an indication that improvement is needed.