The most obvious difference between the devices is the simplest: the screen. The Kindle screen is a low-power reflective e-ink screen that only displays black, white, and shades of gray; the iPad is a full-color, touch-sensitive backlit (emissive) screen that is designed for all sorts of media consumption, including music, movies, full-color magazines, and web browsing.

The Kindle is designed and optimized for reading books and text-focused periodicals. While it does have a (free) 3G wireless connection, said connection is focused on easily delivering content to the device, and light browsing of sites like Wikipedia. The Kindle is a reading device; it tries to get out of the way of the reader, and just provide the words (honestly, once I get into the flow of a work, I often forget I’m reading on a “device”). Even with the recent release of a SDK that will allow app development, I maintain that the Kindle is a limited function device, and I like that. Reading is best done on a device with limited distractions, and the Kindle is just that.

The iPad is designed and marketed for a completely different experience. It’s really more of a “netbook without a keyboard”; I can definitely see it being more of a threat to some of the devices in that market segment. Multimedia from the get-go. For me, it’s not as attractive; I read and listen to more than I watch. I use my phone (Android G1) for podcasts, audio streams, and music, and the Kindle for text (with the G1 as a fairly capable backup). I’m not a big movie and TV consumer.

Another difference, for me, is the Kindle’s ability to stand alone. A Kindle never actually needs ANY connection to a PC whatsoever; you can use the USB connector to charge the device from a computer, and when connected in that way, it can be mounted as a USB Mass Storage device. This means you can drag and drop files both ways…you can copy off your books as a backup strategy, and you can put books on the device that you didn’t get from Amazon. It’s great; but none of that is necessary. You do, of course, have to have an Amazon account to purchase things via WhisperNet, but that’s the limit. You can purchase on the device and have it immediately delivered, or open up a Linux-based netbook, buy the book via browser at Amazon, copy it down to the filesystem, and mount the Kindle as a USB device and copy it over. Works just the same.

The iPad, on the other hand, is tied completely to the same Apple iTunes software stack that the iPod and iPhone are. All purchases and media are sync’d via iTunes…which doesn’t run on Linux, for example. You can’t backup your media (in a supported way) without involving iTunes. You can’t purchase media without involving iTunes. You and iTunes are joined at the hip…at minimum.

The strategies of the companies involved (Apple and Amazon) are interesting as well, and the jockeying between them continues even as I’ve been editing this post. More to come on that and the openness question.