Mozilla has released Firefox 4 beat for Android and Maemo devices, and the web browser is fast on the new Linux platforms. Here is more info from Mozilla:
This release is the fastest performing Firefox 4 Beta for mobile yet with faster start-up, page load times and responsiveness to panning and zooming. How fast?
-Recent tests on JavaScript benchmarks show Firefox 4 Beta is faster than the stock Android browser -Roughly three times faster on Kraken -Twice as fast on SunSpider
Other advancements in this release include increasing stability, reducing installation memory usage, improving readability with zooming, and fixing some keyboard issues.
Firefox 4 Beta for mobile also offers nearly 100 Firefox Add-ons that add features and functionality to personalize your Web experience.