Firefox is one of the best web browsers for desktops and notebooks, but the mobile version of Firefox is a work in progress. And it still needs a lot of progress, because in its present form it's no match for Dolphin or Skyfire. The latest update didn't change that.
First impressions last forever. Upon installing the latest version of Firefox I loaded a website (guess which one?) and was greeted by a popup that said "Sorry! Something went wrong while displaying a web page."
Second attempt worked, somewhat. The site loaded, but Firefox has a problem with text. On most sites the fonts are way too small, and pinching the screen to zoom doesn't help either.
Landscape view didn't look any better. For some reason Firefox decided to leave the right and bottom parts of my screen unused, and font rendering was terrible again.
So I opened some new tabs to see if other sites would look better. Firefox handles tabs better than the stock browser, but not as well as Dolphin. Firefox hides tabs in a side panel without an option to move 'em to the top of the main screen. Accessing your tabs in Firefox works better than in Skyfire, Opera, and the stock browser, but it's not as simple and intuitive as Dolphin. As for the sites I opened, text rendering was a mess for all pages I tried.
So what good things does Firefox for Android bring? It has a lot of add-ons, including AdBlock. The option to send a page to a PDF file is a nice touch too. You'd almost forgive Firefox its lack of Flash support.
But there are other ways to block ads in Android browsers. AdAway keeps ads out of all your browsers and other apps. It even blocks the ads from this site ;) You don't need Firefox to send web pages to PDF either, because Dolphin can do it too with the right add-on. And there's always UrlToPDF which works regardless of which browser you use.
So for now there's really no reason to use Firefox on a phone. You're better off with Dolphin or Skyfire. And if bandwidth is tight then the server side compression of Opera Mini is your friend.
• Firefox (Android Market)
• Opera Mini (Android Market)