I’m using an external keyboard with my iPad to write this. I had an Apple bluetooth keyboard (the newer aluminum one) with a laptop at the office. I consolidated computer setups a couple weeks ago, and found that I didn’t need the keyboard for my Mac, so I decided to try it on the iPad. I was skeptical, in that it sort of takes away from the portability of the iPad. However, after a few days of using it last week, I’m changing my tune. First, as with other bluetooth devices, you can walk in and out of range and reacquire the connection automatically when close enough. That means that I can have the keyboard on my desk, paired to the iPad, and when I leave for a meeting and leave the keyboard behind, the connection breaks; when I come back, it’s there again. Not novel, but sort of a “dock” if you want to think about it that way. Things that are handy are to use the keyboard to wake the iPad from sleep and enter my passcode, to start/stop iPod functions (such as podcast playback), change the volume, etc. Screen brightness can be controlled as well, which is handy, if I’ve been outside and had the brightness turned up, and want to turn it down when I get back to my desk. It really does make entry of text considerably easier, especially if you are a reasonable touch-typist, as I am. It’s also easy to turn the keyboard on and off easily. As you turn off the keyboard, the bluetooth icon dims on the iPad, and you can then use the onscreen keyboard normally. Of course, you can use the “eject” button on the keyboard to open and close the virtual keyboard. I have wondered about battery impact, but in my (so far) limited use, it doesn’t seem to have any observable effect.
All in all, a very useful addition to the iPad, and one that you can take with you or leave behind. That makes it a very flexible solution!