Want to give the Firefox 3 beta a spin, but you don't want to go through the tedium of backing up your profiles and personal data?  Here's an easy solution if you're a Windows user.

The folks at PortableApps.com -- all open source, all no-install, all the time -- have just debuted a new build of Firefox 3 beta 4.  For those not familiar with the PA paradigm, their mission is to provide you with custom builds of the best open source applications which can run without needing to be formally installed.  They can be mounted on a USB flash drive or copied into a directory and run as-is.  They also provide a handy application organizer and launcher which works the same way, and I've stumped for them whenever they come up with a noteworthy new edition of one of their apps.

The best thing about the portable edition of FF 3 b4 is that it runs totally separately from any other instances of Firefox in your system, including your user profiles.  Typically, whenever I tested a new build of Firefox, I had to back up my user profile just to be on the safe side.  PortableApps's Firefox uses its own separate user-profile instance, stored along with the application.

There's a couple of downsides to this.  One is that if you want to use your existing bookmarks, you need to export them from your existing instance of Firefox and re-import them.  The other is that things like password fields aren't inherited, either, but I've been using the impossibly handy (and also open source) SuperGenPass to manage passwords, so having passwords saved in form fields isn't crucial in my case

This isn't the first beta build of Firefox that has premiered through their system, but it's one of the first I feel wholly comfortable working with on a daily basis.  So far it's been extremely stable, markedly faster than even the "accelerated" 2.x builds I've used (like Pigfoot), and racks up a good deal less CPU usage when running JavaScript applications, like many of the Ajax-based tools I use for managing web content.

I'm still getting used to the new ways things like bookmarks are handled -- for one, the "Smart Bookmarks" system doesn't particularly interest me; I don't like it when software tries to second-guess my work habits.  But on the whole I see the finished version of FF 3 in my future -- and frankly, the current beta 4 version is already a big part of my present.