I still have my K1, and got the first Fire about six months ago. I use it for reading about 95 percent of the time, but still use the K1 sometimes. I prefer the Fire, as once I got used to it, I found it easier to navigate through menus, perfect for when I read in bed at night or in other dark places, has more fonts and type sizes, and of course, ability to get online.
However, I usually send a copy to my K1 whenever I buy a book, and sync it if I have to read in a bright place or outdoors.
I rread a lot of free library books on both. I found that I could not send one to my K1 wirelessly if I borrowed the book for the Fire, but they can be downloaded and sent via the USB connections.
If, at gun point, I was required to give one up, certainly it would be the K1, but only in such a situation.
