Kindles are great.
had mine 15 months now, bought other half one for Xmas.
In a month shes gone from a dedicated "real booK" reader to being a kindle fan
I cannot imagine how someone could compare an ipad (or any tablet/phone/backlit device) to a kindle.
So handy and usable, eg on beach with 3G browsing for free, ok it works at caribbean speed

but even so its awesome.
Different devices for different tasks.
the Kodo does indeed look good, as said elsewhere here there are a couple of conversion pieces of software that can convert most published formats to kindle formats.
Text PDFs are easy to convert, small picture as well, large pictures well probably not ideal. I wouldn't recommend them for this scenario, unless you completely needed to have the life of the kindle without access to easy charging, eg out for the day / travelling etc