[tommy still]

I have posted before about using a Cybook with a Mac, but have still not taken the plunge, the fact that there is no software needed to sync is great, just drag and drop. I have just read on the Bookeen site that the reader software is upgraded by the SD card. Is this simply downloading a file and copying it on to the card to install to the reader, or is Windows software needed somewhere along the line ? Another problem I am not quite clear about is buying books with DRM, if I dont use the Mobipocket windows software for instance how do I download a protected book to a Mac ? I know about each device having its own unique ID number, can I enter this number on the website somewhere along the purchase path to allow the book to be read, or do I have to resort to Windows again ? After I have read the book will there be any problem in copying it back to the reader at a later date to re-read ? I am sure these questions have been asked before so sorry to ask them again.
One more thing, I find it strange to be considering spending money on a device I cant even handle before I purchase, the same goes for all the readers as I live in the UK, and as far as I am aware none of them are available over the counter. Thanks in advance for any help.