A couple of months ago I boasted about how great PortableApps was as a collection of software that could be ran from a USB drive.  Not long after then my work bought me a 4GB ScanDisk Titanium Cruzer which is much better than the same size EZCool drive I had bought and included U3.

A U3 smart drive makes any PC your own PC. And when you unplug it, it leaves no personal data behind. 

Watch the video on the U3 site and it all sounds pretty impressive, but in reality it's not that special.  It's implementation and limited software holds it back.

Plug you're U3 drive into your PC and the U3 laucher will load in your system tray.  It's like a second start menu, not much different to PortableApps, that lets you launch U3 applications from your pen drive.  New software can be installed easily by downloading the file, and running the file whilst the U3 drive is plugged in or installing it via the launcher.

Unfortunately, whilst U3 could have pretty reasonably nice, it falls short of being something really good for a number of reasons.

The ability to take your desktop with you isn't as unique and clever as it sounds.  It's simply a program that backup your  e-mails, internet favourites, desktop wallpaper, etc to your pen drive and then gives you access to them from the application itself.  And it pretty much only works with Microsoft software (i.e. Outlook, Internet Explorer).  It doesn't load a magical portable desktop when you plug in the drive and then unload it when you unplug the drive.  It's simply a synchronisation program, allowing to copy your setting to the new computer if you choose.

Installing software can be very easy via the launcher.  Not only can you simply load the u3p file, but you can browse the U3 website via the launcher and install new software with a click.  This convienence is let down by the fact that the site has no facility to search which means you have to scroll through pages of software to find a specific application.

The whole format of U3 applications is surprisingly un-cryptic.  Download the installation file for a U3 program and it'll install onto your U3 drive automatically in a hidden folder called 'system'.  Each program has it's own folder which appears to be named with a random string of characters.  Look in on of the folders and you'll find a .u3p file.  Now this is the strange part, you must have a U3 drive plugged in to your PC to install the U3 software, but once it's installed that u3p file can be copied, renamed to a zip file, extracted, and then run the extracted exe from any non-U3 drive.

The simplistic nature of U3 software means it's not terribly difficult to create or convert software to a U3 program.  Someone has even written a wrapper application to redirect any attempts by the software to read or write files on the local file system back to the pen drive.  Although it takes some manual scripting and I didn't have time to investigate how effective it was.

Despite the relative ease for software developers to make a U3 version of their application, most don't.   Applications like KeePass offer 3 portable versions and the U3 one is out of date.  For a long time only Firefox 1.5 has been available.  And if you have a simple application that can run without installation, such as Process Explorer, you can't make appear in the launcher without converting to a U3 package.

Another negative is that the U3 system works by loading CD image in a virtual drive in addition to the USB drive itself.  This is forgiveable though.  One great things with U3 is that it can lock down the pen drive so it can't be accessed until it's unlocked with a password.  This is obviously why a virtual CD drive is created so the U3 launcher still can be ran to unlock the drive.

So if you want to password protect your pen drive, the U3 system is quite useful.  But as a system for carrying your applications, I think most people will prefer PortableApps.