One of the advantages native apps have is that they're easy to find: Launch the App Store app, type Kindle, and in a few seconds you've downloaded and installed the Kindle app on your iPad's home screen. Adding the Kindle Cloud Reader is a bit more complicated.
First, you have to open Safari and visit read.amazon.com. Amazon will ask you to log in with your Amazon.com user name and password, and then you'll be prompted to authorize an increase to the amount of data Amazon can store on your iPad--essentially carving out 50MB of space to download books for offline reading.
At this point, the best thing to do--and I'm surprised Amazon doesn't actually step you through the process--is tap the Share icon in Safari's toolbar and choose Add to Home Screen. This will create a new Cloud Reader icon on your iPad's home screen, complete with custom icon. Tap on it, and Kindle Cloud Reader will load again--this time without any web-browser interface trappings. (It'll even show up in your list of running apps when you double-tap the home button.) Unfortunately, you'll need to log in to Amazon.com again and authorize the offline data storage a second time.
Compare and contrast
Though the home-screen icon and lack of browser chrome makes the Kindle Cloud Reader feel like a native iOS app, there are still some notable differences.
Everything in the web app is a little slower, a little less responsive. But it's still a remarkable emulation of the app experience. Like the native app, there's a home screen full of book covers--by default the Kindle app shows you the items on the device; the Kindle Cloud Reader shows you all the books available to your account. Scrolling through the book covers is not as smooth as scrolling in the native app, nor does it feature the intertial-scrolling effect that gives scrolling in an app that extra something. Taps are sometimes not registered, or are registered much later than you'd expect.
To store a book for offline access, choose Download and Pin.
To read a book in the Cloud Reader, just tap on its cover art; while tapping in the Kindle app will download the entire book to your device, the Cloud Reader web app will start loading the book over the Web and display it right away. To store a book locally on your device in the Cloud Reader, you must tap and hold on its cover, then tap "Download & Pin Book" from the resulting pop-up menu. To see all books that have been downloaded, you tap on the Downloaded tab at the bottom of the screen.