In an introductory video, Mozilla staff talk about an emphasis on speed and performance, highlighting how common tasks like page zooming are handled as separate processes to make the experience as smooth as possible.
We downloaded the beta to an HTC Desire and we were able to see the speed immediately. Page loads are about average for a mobile browser, but once loaded the content rescales seamlessly when using the pin-to-zoom touchscreen gesture.
Those who are familiar with Firefox will appreciate some of the fidelity to its desktop counterpart Mozilla has managed to bring to phones. Firefox Sync is pre-installed, which gives you access to history and bookmarks from other Firefox browsers. There's also an add-ons component, allowing you to customise your browser with tools developed by Mozilla and third parties.
Our only criticism from our brief experience so far is that there doesn't seem to be any way of setting Firefox to identify itself as a mobile browser. The browser will load full desktop versions of sites by default, meaning you'll make good use of the speedy zooming and panning as you'll need to zoom in on every page before making it legible on the small screen.
If you want to try out Firefox on your Android phone or N900 point your mobile browser to the beta download page at Firefox.com/m/beta. Mozilla predicts compatibility on all Android phones running version 2.0 or higher, but let us know in the comments if you have any trouble installing it.