Although MyInfo 3 could be installed on a USB flash drive, it works far from perfect. It could not store user settings back to the flash drive and in general it is not designed for such a purpose.
In MyInfo 4, we have paid a special attention to the ability of the application to run on a USB drive. Now, all user settings are stored back on the USB drive. Even little things as your personal spelling dictionary are remembered between the different host computers. There will be separate install package of MyInfo, especially designed for portable installation.
The pros of using MyInfo (or any other application) on a thumb drive is that you can always have your favorite application and all your data with you. In addition, the backup of such installation is extremely easy, because all files that you have to backup are stored in a single computer folder.