moved to a K2i last December or so...had the K1 since it's first year but did not use it much because, well, I did not care for it much and it was co-opted by the better half...eventually it "became" mine when we got her a K2US at which point I tried it for longer than a few days and figured it was fine...then when I found the $100 discount for signing up for an Audible account (something I do anyway) I decided that $159 for a K2i was a reasonably OK price.
I have to say the difference in how the side buttons work is huge. The fact the K2 buttons press inward vs. outward on the K1 makes a really big improvement in the handling for me. No longer do I change pages by some random amount based on how long it is before I realized I was holding down the button when changing hand position.
I don't like the K2 keyboard at all, it's cramped, awkward, lack of two shift keys and the funky access to the extended symbols is just horrid.
Had I not found the deal via Audible $100 credit I would have purchased a Pocketbook 360 as it better works for my idea of a portable recreational reader with it's size and integrated hard cover. Perfect size for paperback type books to my eye.