Firefox 4 Mobile may not be the droid you're looking for
Mozilla has had a long and somewhat frustrating experience trying to build a mobile web browser. They failed with Minimo, they started again with Fennec in 2008, specifically targeting Maemo.
Then Fennec morphed into Firefox Mobile, which hit its 1.0 release earlier this year - again only for Maemo, but with a goal to expand to other platfoms including Android.
So here we are more than two years after Mozilla kickstarted its mobile efforts, and they've announce the first beta for Firefox 4 Mobile on Android and Maemo. So forgive me for not being too excited about the this new beta, I've heard this song before.
The ability to sync desktop and mobile is a great idea and that's likely the ideal use case scenario under which Firefox 4 Mobile will thrive on Android devices. For iPhone users, there is no Firefox Mobile, but they can benefit from the Firefox Home application instead.
Choice is always a great thing, though in my experience the Android web browser is already a fast and very capable technology. It's not like Windows users with IE that really need another option, Android users aren't exactly suffering. Blackberry users, now that's another story -- I haven't seen any effort from Mozilla to target that platform (and likely won't either).