iPad 1, iPad 2, iPad 3 iPad 12, it doesn't matter how far they go, the Kindle will remain the best device to read eBooks.
Why ? Because it's an eBook reader. Period.
One could go on and on about comparing features offered by the iPad and other Android tablets, but the Kindle simply embeds the right technology to offer the best reading experience. It took me a long time to get myself one of those, but there are the reasons it surpasses by far all the other tablets:
It doesn't do anything but offer one feature: eReader. No apps, no mp3, no notification, it's plain and simple, it reads eBooks. Resulting in all the advantages below...
It's exactly the right size, and lighter than a pocket book
Let's not talk about brightness, contrast and pixel density.. Kindle use real ink to draw text and images, it's black and white, but so are 99.99% of real books, and that's fine that way. No pixel mean no red eyes and headache, it's like reading real sheets of papers.
Also, it means one can take it to the beach or other sunny environments.. let's not try that with an iPad.
1 or 2 months, it doesn't matter, we are talking about weeks of battery life here.
Oh and it's almost 10 times cheaper, the most basic model offers all one coud need, this means it's affordable, and less likely to be stolen. And if it breaks... oh well let's buy another one.