I don't have a card reader, but it sounds like that may not be such a bad
thing to get, except that it is probably more hassle to eject the SD card
and reload it into a reader and run the risk of damaging it from
frequent handling.
Contrary to HS I haven't found the card reader to be noticeably faster, but
it does have the advantage of working even when the camera doesn't
(e.g. when the battery is empty). Also of course it uses the UMS
(Universal
Mass Storage) protocol which is very well supported under GNU/Linux.
I think that my immediate concerns are now sorted - I can successfully
retrieve images taken. The less pressing issue, but one that will bug me,
is
the difference between the 2 cameras on one hand and the the difference
between the 2 machines on the other hand.
Regarding the difference between the two cameras I'd simply look at the
protocol they use: most likely the Sony machine uses UMS whereas your Canon
uses PTP (Picture Transfer Protocol) which is more recent and less
well supported. You may also be able to change your Canon's config to
use UMS.
Stefan