Opera Mobile and Opera Mini
Opera has two mobile browsers: the full-size (12MB) Opera Mobile, and the smaller (767KB) Opera Mini. Opera Mini sends your page requests to a server, which compresses them before sending them to your device. This arrangement makes browsing with Opera Mini much faster than browsing with Opera Mobile. On the other hand, Opera Mobile does a better job than Opera Mini of rendering pages to look the way they would on your desktop.
Opera Mini can load image and Flash-heavy sites in seconds, and it supports tabbed browsing so you can open multiple websites at once. The Opera Mobile browser is quite fast, too, and it offers the same features as the Mini. Unlike Firefox and Dolphin, however, the Opera browsers don't support add-ons. Instead, Opera loads its browsers with its own Android app store--accessible through the start page--so you can download Android apps like Angry Birds and sideload them onto your device. Because Opera's apps are curated, there are a lot fewer junk apps to contend with; but if you don't have a device that can sideload apps, the store will be useless to you. Both apps also have a synchronization feature for syncing your mobile bookmarks with the desktop version of Opera.
It's hard to beat the stock Android browser. With pinch-to-zoom, Flash capabilities, and a decent downloads manager, the Stock browser can handle just about anything you throw at it. It may not have the speed of Opera Mini or the customizability of Firefox and Dolphin, but it is handy for quickly searching online, and it integrates well with other preinstalled apps. You can share pages via email, Facebook, Twitter, or even text message. Unfortunately the stock browser gets updated only when Google updates the operating system--so if something isn't working, the patch may take a while to arrive. Regardless, the stock Android browser is great for people who want something that works right out of the box.
So Which Browser Is Right for You?