Costing too much, at the moment, but prices are bound to fall from now on. Remember when we paid R300 for a DVD a few years ago. But just like your solar geyser it has a payback period which could be anything from a year to 3-4 years depending on your profile. And you save trees. And you have all your books (in my case references, technical texts,dictionaries, etc) in one small thingy instead of having to lug around cases full of books. (Kindle is also more expensive than it could have been because it has free a 3G data plan included for the life of the device - although in South Africa we are currently limited to wikipedia access only in addition to the Kindle online store.)
Availability in SA ... problematic. Most are not on sale in stores yet, as far as I know.
But Amazon ships the Kindle to your door for $25, so it's hardly a problem. One or two other of the other device manufacturers also courier to SA. Or you can use importers like take2, have2have or wantitall. But beware their prices are crazy. If you are interested in the Kindle, order directly from Amazon.
Amazon takes a loss on shipping this thing to SA. That's one thing, but a device which is not ideal for me, no matter how cheap will not make me buy it.
The competitors either ship directly to SA or you can purchase the device through 3rd party services or shops. The Kindle is tailor made to read Amazon ebooks. It does that very well. However, it is not designed - purposefully to do other things because that does not contribute money to Amazon. If any open features emerge it will only be because the Nook and other readers have them and Amazon will be afraid of competition. However, there is a clear conflict of interest between being a hardware manufacturer and a content provider - if you're the same company. This exists in Apple products. It exists in Sony products. It also exists in the Kindle.