i installed this, works great for me. I remember the last official FF for maemo and it was so slow and cumbersome, all i saw was the checked background, it froze, crashed, wouldn't load things, nightmare. For a long time i stopped using FF on the N900 altogether. The betas improved it and now this is, for me, a perfectly working browser.
MicroB is my main browser, always will be, but i use firefox for when i'm away from the laptop and want my tabs/information synced