[gwynevans]

While I get the impression that the Sony feels sturdier than the Cybook, (and the metal casing does mean that the Sony doesn't feel too light, which sometimes things do,) I'd hesitate to suggest that it's a good idea to expect either to survive much of an impact, as basically, both share a display that's in part, a very thin piece of glass.

I'd suggest that you try & evaluate how much the PDF capabilities mean to you, but be aware that there are software packages available that mean that a significant amount of format conversion is possible for each, if you see what I mean.

As far as the Sony goes, it's also able to read ePub, which hasn't been mentioned but may be useful, but as far as PDF goes it can read normal (A4) PDFs marginally (which is down to the nature of the 6" screens rather than anything else), although it can rotate 90 degrees to display them landscape, which is sometime useful. As for the reflow, it will resize & reflow the text such that it can be easily read, although you then miss out on any diagrams or pictures.

I don't think there's anything that strongly suggests one or the other - ePub, PDF & 'feel' for the Sony vs dictionaries & multiple fonts for the Cybook... Either way, don't do anything for a few days as Sony has got some sort of announcent due next week.