The E-125's strongest feature is the color screen. The obvious comparison is to the Compaq iPaq 3600 series, which is bright enough that you can literally use it as a flashlight. The E-125's screen is bright enough to make the Compaq screen seem dim. It also offers 65,536 colors rather than the Compaq's 4,096 colors, which can make a big difference if you want to view photos. Alas, setup is more confusing than it should be, with instructions spread out over a number of loose pages.
Notes includes a handy recorder that takes advantage of a built-in microphone and speaker.
The package also offers programs that improve on these core applications and share data with them. You can, for example, use the Windows Calendar or Casio's Mobile Calendar. Enter data in either program, and it's available to the other. Similarly, you can use Contacts or Casio's Mobile Address Book. The 32MB RAM offers plenty of room for data or additional programs, and the built-in CompactFlash card slot provides room for expansion.