The e-ink technology on the Kindle is far superior to anything that Apple has today. You cannot read or even see the content of an iPad (or iPhone) screen outside in the sun (I know, it's Oregon -- what sun
).
The other problem with the iPad screen is that the high-gloss surface seems to be a magnet for finger prints, etc. which make the screen hard to see without having to clean it often.
I am not trying to say that the iPad is bad -- I just don't think it is perfect for every application and the Kindle is s superior device for reading.