There's a HUGE difference between an eReader and a tablet. People who don't regularly read don't understand this. Many people think the iPad is a good eReader. But that's like saying a Koenigsegg is a good commuting car.

Think about what makes a good eReader:

  * Very light
  * As small as possible (while retaining page size)
  * Long-lasting battery
  * Good reading screen

With this in mind:

  * iPad as an eReader = fail
  * Kindle Fire as an eReader = fail
  * Most tablets as eReaders = fail
  * Standard Kindle as an eReader = excellent

Personally, I can't justify a tablet, but I can absolutely justify an eReader for actual reading. As soon as I saw the announcements for the new Kindles, I saw that the $79 version was the smallest and knew it was the best of the bunch. The Touch is somewhat interesting, but every gram matters when you hold the device for 2, 3 or even 4 hours straight.

I bought an iPad 2 this year and haven't gone back to my Kindle DX since I got it.

The Kindle has a huge advantage in battery life and some advantage in weight, but neither of those are critical in my experience (iPad battery life is sufficient for a day's use, which is good enough for me, and weight is close enough).

e-Ink and LED screens each have advantages in some lighting environments. For my purposes (indoors, airplanes, low light), LED works better.

The iPad has a huge speed advantage over the e-Ink Kindle, which comes into play for any activity with an eBook that goes beyond "read a page/turn the page". Finally, the iPad has better fonts; especially for technical material, the fixed-width font on the Kindle is incredibly annoying (with e.g. the dot on the "i" near-invisible).

[Full disclosure: I work for Apple, but in non-iOS engineering]