There is not a huge difference between this and the MV550E.
In fact, if you put them side by side you have to look closely to see the difference in looks, which is model number in small print on one side.
Internally, the MV580E has a more powerful, 1 megapixel (570,000 effective) CCD and will produce 1280 x 960 (1.2MP) still images compared to the MV550E's poor 640 x 480 stills.

Both cameras ship with a single sided DVD-RAM disc but susprisingly no memory card.
The single sided disc gives you about 30 minutes of recording on the Fine setting while you can double that for the double sided DVD-RAM disc. You can only do in-camera editing with the rewritable DVD-RAM discs, although the camera also accepts write-once DVD-R discs, in which case you have to transfer the images to computer either by USB or direct from a finalised disc for editing and burning to a new disc.

The recording quality of the camera is a lot better than the initial playback on the LCD screen suggests. Once you transfer your video recording to your PC, the quality improves dramatically and the image doesn't suffer the same drastic changes in light that playback on the LCD suggests it does.

The video playback on computer is good quality and not as dark as the image from the MV550E. However, even if it was, it is easily rectified by the cameras internal lighting and contrast settings.

The battery pack on both Hitachi's is rather large and as a result it makes using the viewfinder uncomfortable as your cheekbone ends up pressed against the battery.
Aside from that, the camera is very comfortable to use, fitting nicely into the palm of your hand.

All the controls on the camera are intuitive making the camera a breeze to use, once again following the principles of point and shoot. The on screen display is clear and concise and the menu is navigated using a small joystick. While everything is uncluttered it also means that some features are missing such as a Night shooting mode.