In addition to a redesigned UI, the new version of Firefox Beta is promising "significant" improvements in performance, which sounds great, but it has also become also as expected as the promise of generic "bug fixes" in each release. The browser also has a new start page, but maybe best of all is that it has finally added support for Flash.
Part of how Mozilla was able to up the performance and other improvements was by bumping up the minimum requirements for Firefox Beta. So, now instead of requiring Android 2.0 or higher, you must have Android 2.2 or higher. Of course, that still covers the vast majority of the ecosystem, so it shouldn't be a problem.