Amazon Kindle vs. Apple iBooks

It seems that the available content with Amazon and Apple is roughly the same, so which is the better product - Kindle or iBooks?

Some features that are better with the Kindle:

• You can read books on a Kindle device in bright sunshine. Reading in bright light is difficult with any iBooks enabled device.
• You can read your Kindle books on any of the following devices: Kindle (Keyboard, Touch, Fire...), Windows PC, Apple Mac, Android Phone, Android tablet, Windows Phone, iPhone, iPod Touch or iPad. With your iBooks books, you can only read them on the last three devices.
• The Kindle has a built in French - French dictionary, if you read French but need help with some words.
• The Kindle has a built in Italian - Italian dictionary.
• The Kindle has a built in Portuguese - Portuguese dictionary.
• The Kindle has a built in Spanish - Spanish dictionary.
• The Kindle has a choice of UK or US English dictionary. iBooks only has one English dictionary, as far as I can tell.
• Pages turn quickly and the application loads fast in the Kindle readers. iBooks is substantially slower in my experience. On the iPhone 4G, iBooks is hardly even usable.

Some features that are better with iBooks:
... This section will be updated as soon as I come to think of any.