Sony has very kindly loaned me one of its PRS-505 electronic book devices to try out.

In particular, I wanted to see how it would measure up as a medium for carrying around Microsoft Word and Acrobat PDF files for reading on the move, as the alternative is to print them out or load them into a PDA or laptop.

The first thing worthy of note is that the 6in display of the eBook Reader has to be seen to be believed. Although only black-and-white and lacking a backlight, it has such a high display resolution that it resembles more a printed page than any other computer screen I've ever seen.

So how does it double as a mobile document reader? Sadly, not too well. It's easy enough to get files onto the eBook Reader, but while PDF files are supported natively, Word documents are not and must be converted to RTF format first.

And while the text in PDF files displays very well, any embedded images or graphics can only be seen in the entire page view; zoom in, and the graphic simply isn't displayed any more.

But the eBook Reader is really designed for looking at books, specifically those published in the EPUB digital format, and Sony supplies the PRS-505 with excerpts from several titles in this format for buyers' to try out.

The eBook Reader is a nice size and weight for the job. It is just a bit smaller than a sheet of A5 paper, weighs about 260g, and comes fitted into a leather-effect cover that makes it look like a notepad when closed. The device itself appears to be made of brushed steel, and feels like it is built to last.

Overall, the eBook Reader is fairly easy to use, but it seems to have too many controls. There are ten buttons labelled 0-9 down one side of the screen, plus two navigation controls, dedicated next-page and previous page keys, as well as tiny buttons to zoom in and take you to the main menu.

The eBook Reader has two slots for Sony Memory Stick Duo and SD Card Flash media, from which it can read files. Users can also load files onto the device over a USB cable from a PC using a supplied Windows tool called eBook Library, which seems to have been designed to imitate the look and feel of Apple's iTunes.

One advantage the PRS-505 has over other electronic devices is that its E-Ink "Electronic Paper" screen uses much less power than standard LCD technology, and consequently the batteries last much longer than those of other electronic devices. I used the PRS-505 for several days before the battery charge indicator went down even a single step.