[Thunderbolt General] yareally:
Everyone has their own choice of browser as you can see. However, that doesn't mean a particular browser wont have features or semantics that wont appeal to you more than others, so try them all and see.

For the record though, I prefer Opera Mobile, but I also use Opera on my desktop as the main browser as well. However, some browsers do certain things better than others. I prefer firefox (for firebug and dynatrace http://www.dynatrace.com/en/) when I develop and SrwIron (chrome) is my fallback browser on the desktop if Opera wont work on a site.

Opera probably has the longest development track record (starting years ago with windows phones and symbian) for a mobile browser (and one of the longest for support on ARM processors in general). All but a wrapper that calls the code libraries (.so files or for those that stick with windows, .dll files) in Android's dalvik vm are compiled natively for ARM in c++ (since they use these libraries on windows phones and symbian as well), so they have the ability to run faster than the code that must be interpreted through the dalvik virtual machine. See http://my.opera.com/operamobile/blog/the-components-of-opera-mobile-11-on-android for more details on that.

Opera will also allow you to sync your browsing history, bookmarks, search history, favorite pages (the speed dial), etc to the desktop version if you use it. http://my.opera.com/desktopteam/blog/my-opera-synchronization-explained

Opera also has a pretty good track record for security and patching exploits. I'm leary of trusting any browser other than Opera or the native one built into Android, which has similar libraries as chrome (firefox mobile is probably okay as well, but it's still in the development phase so there could be bugs or things not patched quite yet). The rest of the mobile browsers other than firefox mobile (built on gecko) and opera (built on presto) are all mostly close to vanilla webkit clones (excluding the built in android browser similar to chrome) that aren't overly proven to be secure or have a long history of development. Since they're webkit clones (since webkit is currently the only stable open source platform choice for phones until the release of a stable firefox mobile), they're all going to tend to look somewhat alike and have similar speeds. That's not to say they are not secure, but they're mostly rookies to the game compared to Chrome/FireFox/Opera. Webkit rendering engine itself is well designed (with a history of being used on mobile phones long before android via nokia's built in symbian os browser), but how companies take that code and implement is is the problem. In the pwn2own hacking competition, chrome (the desktop version) was the only webkit based browser not to be susceptible to a major exploit.

Opera has its little annoyances like any browser. Mostly things like being ignored by bad web developers in the past that only cared about IE. However since firefox and chrome follow web standards like opera now and have a significant market share, this rarely happens nowadays. Though, sometimes I will stumble on a site using the desktop version that forgets Opera is also a desktop browser and gives me the mobile page, haha. For quite a while, McDonalds.com would do this.

Any of the more popular browsers should be good enough if you use good judgment, but if you're ever leary of a site, at least pick a browser you can disable plugins (flash and pdf readers) and javascript if needed, since those are the 2 main ways you might get hacked via a web browser. In opera mobile, you can type "opera : plugins" (without quotes and the spaces) in the url and you can disable any plugins you do not want to use. With that it's generally harder to monitor the system internals and connections on your phone versus a desktop pc (and the wonky permission control system [or lack thereof] in the graphical interface of android), it's better to be a bit more cautious.