I started to use the Kindle Fire for reading and other media consumption recently. I noticed the ebook reader is better than the software version on iPad for mainly two reasons: 1. the hardware on Kindle Fire is probably optimized for reading, the pixel count seems to be higher so that the font looks a lot sharper than that of iPad; 2. Amazon gives more features to its own reader such as type-face adjustment than that of the iOS Kindle app.
The first one can only be corrected by a new retina display based iPad next year. The second one will depend on the market competition between Amazon and Apple. May the best product/service win!