Firefox 4 Release Candidate (RC) version is now available for download that is to be used for Android and Maemo platforms and the final version is on the way, which is expected to be launched in the next week. The RC version brings more stability and it is just a work of spit and polish. In case of usability-wise, the release note that is made available by Mozilla on its site, contains 150 add-ons that works perfectly with this mobile version of Firefox 4.
This version comes with Firefox sync enabled and Form Assistant which makes logging to a website easier. The most advanced features this RC version brings with it is infamous checker boarding from page rendering and scrolling, thanks to smarter rendering and page loading algorithms.
Finally, this version also contains a link to Firefox Spark, a new badge-collecting website which seems to be one of Firefox 4 for Android launch goodies.
To download Firefox 4 for mobile, go to this link.