The ROMs people here refer to are different sets of flash; containing OS parts, kernel, and other juicy bits. The native ROM from Sharp is localized in Japanese, though much of the localization can be changed to English.
The Sharp ROM uses Qtopia from http:///www.trolltech.com which is a
GUI targeted for PDA and other embedded devices; it\'s nice for PDA
functionality, but isn\'t a Linux/Unix standard interface, and tends to run
only software written specifically for the Zaurus.
The CaCko QT ROM starts from the Sharp ROM and fixes a number of bugs
and adds extra funtionality; while dropping a few things like the Dictionary.
The CaCko pdaXrom uses X11 - the standard Windowing GUI for Unix;
and it can run (after recompiling) most Unix software. If you want a small, ordinary Linux box to experiement with, pdaXrom is a good bet.
The command-line interface is very similar for all.
All the non-Sharp roms are experimental, and under development.
There\'s a small chance of leaving your Zaurus unuseable from a bad flashing, or from badly placed instructions in the command shell,
but in nearly all cases, re-flashing will fix things.
One thing to note- the keyboard *is* small, if you have small fingers you\'ll find it more useable. I\'d say its better for a second-computer than a primary one; but is really serviceable for either.