Tabs: Getting to tabs in Fennec is so easy it's ridiculous. Just flick the web page to the right and you can easily add or close tabs from another sidebar. This is a fantastic feature, and will make mobile browsing far more productive.
Flash and other video codec support: Fennec boasts the ability to play anything from Flash to Quicktime to Silverlight. However, in our tests Fennec didn't fare well for playing video.
We accessed YouTube, the New York Times, and CNN to test video and none of them worked effectively. On YouTube we could get audio but no video (we couldn't even see the actual plugin), at CNN we couldn't even get the video to play, and at The New York Times the video was incredibly jumpy and was more like watching a slideshow. We hope these problems will be fixed before an official version of Fennec comes out.
Despite its video shortcomings, Fennec looks like a fantastic browser for the mobile web. According to the roadmap, the first devices to get Fennec will include Nokia's Maemo platform and Windows Mobile 6, followed by Symbian devices (work on Symbian begins in December 2009). Currently, there's no news to report for Palm, BlackBerry, or Apple iPhone users.
It looks as though Mozilla Fennec may prove a worthy rival to Opera Mini. If you're dying for a sneak peak at Fennec you can download the real thing for the Nokia N810 tablet or emulators for Windows, Mac OSX, and Linux.